Ostensibly, Paul does explicitly say what he believes the women were doing.

"IN THE SAME WAY...."

Paul first states that women exchange natural sexual relationships for unnatural relationships. Paul then moves on to men who he also claims abandoned natural sexual relationships for unnatural ones. However, in doing so, he draws a parallel or a correlation. That which the men have done is the same as what the women have done, that's why he bridges the two statements with "In the same way." So, he's drawing a direct correlation between what the women did and what the men did. This is a normal rhetorical device. There is no need to repeat the same list of activities twice. Nonetheless, it is safe to understand that all the things he is saying the men were doing he was also saying the women were doing.

The question/issue here is in the arguably awkward way he sets this up. Normally, an author sets out the list and then indicates it's repetition without actually repeating it. But here, Paul does the reverse. He saves the list until last and retroactively applies it to what he's already written. Why? The short answer is it is still being debated.

There are several issues it helps to understand: what Paul was writing, how Paul wrote and how the Greek language Paul was using worked.

First, we have to look at what Paul was writing. Romans is considered an epistle, which really just means it was a letter written by Paul to some other person/group of people. In this case, it was written to the Christian community in Rome, or to the "Romans." All of Paul's writings contained in the New testament are epistles/letters. But they aren't all the same type of letters. Some of them are clearly very personal letters written to specific individuals who Paul clearly knew well and deal specifically with those people's specific situations. A great example of one of Paul's very personal letters is the letter to Philemon. There, we can read Paul as speaking directly to a very specific situation and what Paul writes should be understood in the frame work of that situation. However, arguably, Romans is on the other end of the spectrum. It isn't certain Paul knew anyone in Rome or had ever been to Rome. Moreover, Romans is, again arguably, more a theological work espousing Paul's understanding of God and Jesus than an intimate communication between people addressing shared problems. This leads to issues when reading Romans and Ephesians and Paul's other "theological" epistles of trying to decide when Paul is addressing recipient specific facts or just espousing general theology? So here, is Paul citing to "sexual immorality" that the Roman's specifically would have been ware of and may in fact have been happening in Rome, or is this more Paul arguing that a denial of God leads to an unnatural existence and behaviors? It's not 100% clear. It seems Paul has specific instances in mind, but jump down just two and three verses to 29 and 30 and Paul has moved on to a general list of anti-social behaviors which he also attributes as the natural consequence of denying God (which cause the unnatural sexual relationships in verses 26 &27). This general listing seems to indicate that the whole may just be a theological argument that the denial of God leads indulgence which leads to unnatural activities which leads to personal and societal degradation. And, in my opinion, this is the proper way to read chapter 1--as rhetoric. Roman's is Paul's seminal statement on God and Jesus. It makes sense to open that work with an overview of why God, and the correct belief in God, is important; both on a micro and a macro level, which Romans 1 seems to do. As such, there isn't necessarily any reason to think Paul had specific instances or examples in mind.

Second, there is HOW Paul typically wrote. When writing his theological, and therefore much longer, letters, Paul often employed an implication/analogy style of writing. What I mean by this is Paul would often frame his writings in a parallel style. Imagine a ladder--two rails connected by rungs. Paul would have two parallel ideas. He'd write about one and then the other. And, by how the writing was laid out, a reader could understand that what Paul wrote about part 1 dealing with issue A could be applied to understanding part 1 dealing with issue B. An example of this is in Ephesians where Paul writes about the relationship between Church and Jesus and then writes about Brides and their husbands. Romans 1:26-27 seems to be a quick version of this, which can also be an introduction by Paul as to his writing style, which is helpful IF this is his first communication with the believers in Rome.

Finally, it helps to understand how Greek worked. I'm not an expert, but I studied Greek several decades ago and retain some basic understanding. The short is that Greek is a "case ending" language. What this means is that how a word was written would change depending on the role that word occupied, especially for nouns. So, in English we have the word "word." Other than to make it plural, it is always written as "word." But, that's not how it was written in Greek. In Greek, it is "logo." Except, you would never write "logo" in a sentence. You would write, "logos" or "logon" or "logoi" or one of a couple of other forms depending on what role it had in the sentence and how it interacted with the rest of the writing. Similarly, verbs were subject to being written differently depending on their role and what nouns they were playing off of. The result is you may have a long passage where in you have to understand what key phrase the rest of the passage is referencing by implication. We read English and want (and usually get) an article for everything, but that's not necessarily how Greek worked, and usually wasn't how Paul wrote. An example of this is in Ephesians 5:21-22 (which I've already referenced above). Verse 21 has all Christians submitting to all other Christians. Ephesians 5:22 is famous (infamous) for commanding wives to submit to their husbands. However, the term submission isn't found in verse 22. It is clearly in verse 21 which commands all Christians to submit to one another. The issue is that there isn't a verb in 22 at all, but verse 22 is clearly establishing a relationship between wives and husbands, i.e., wives are to do something in regards to their husbands, but what? There isn't another clear verb until you reach verse 25 wherein husbands are commanded to love their wives. So, is the implied verb in verse 22 submission being carried over from verse 21 or is it looking forward to verse 25 wherein love is the clear action? (Verse 24 strongly indicates its submission as it seems to close that set of instruction with a final re-reference to the church relationship which is characterized by mutual submission). So in Roman's 1:26, most scholars interpret the implications to refer to later assertions, but in Ephesians they interpret in the implications to refer to prior assertions--which indicates Paul isn't always consistent and that there is always some guess work. This is all to say that sometimes, it's a guess as to what, exactly, Paul wrote (like when he he writes 5 sentences in Ephesians, but only has 2 verbs).

So, what you're asking is a very legitimate question. It's one still being debated by theologians and historians because there isn't a clear answer. It just isn't certain if Paul is condemning homosexuality, or maybe sex in religious rituals, or maybe prostitution/slave sex, or even pedophilia. Or, is it simply anything "unnatural?"

Fantastic answer. Thanks for the engaging brain food 🙏🏻