Trying to answer this question illustrates two major problems in social history. Firstly, for much of history, our corpus of evidence focuses overwhelmingly on the elites of society and their culture; there's a reason that pop-history of the Romans focuses on toga-wearing patricians eating honey-roast doormice in their palatial villas, and not people dying of plague in their cramped, crumbling insula, or why the 1920s is 'flapper dresses and motor cars', not the General Strike of 1926 and the economic crisis caused by Churchill screwing up the gold standard and tanking the coal industry. Secondly, it's hard to overemphasise the lingering impact still felt from the very white, upper/middle class, socially conservative, colonialist, Christian lens of 19th Century historians, a school of often-teleological history which academia only began to firmly challenge (with some exceptions) in the 1960s and 1970s, and which remains entrenched in a lot of public history to this day. In the context of your question, what this means is that a huge amount of what we might call 'period humour' was either not recorded, or was retroactively sanitised by later historians because it didn't quite fit the image they were looking for.

Somebody who went to a British school in the 1930s-70s and learned "traditional" English folk songs might be forgiven for thinking that their ancestors mostly sang about flowers, going to fairs, and how noble it is to die in the service of Empire. They'd almost certainly be shocked by songs like "Put In All", a wildly popular song from the 18th Century about an enthusiastic but poorly-endowed man who struggles to satisfy his lover, who is what I believe the kids today refer to as a "size queen":

A young man and a maid, put in all, put in all!

Together lately played, put in all!

The young man was in jest,

The maid she did protest:

She bid him do his best, put in all, put in all!

With that her rolling eyes, put in all, put in all!

Turned upward to the skies, put in all!

My skin is white you see,

My smock above my knee --

What would you more of me? Put in all, put in all!

I hope my neck and breast, put in all, put in all!

Lie open to your chest, put in all!

The young man was in heat,

The maid did soundly sweat:

A little further get! Put in all, put in all!

According to her will, put in all, put in all!

The young man tried his skill, put in all!

But the proverb plain does tell,

That use them ne'er so well,

For an inch they'd take an ell! Put in all, put in all!

When they had ended sport, put in all, put in all!

She found him all too short, put in all!

For when he'd done his best,

The maid she did protest:

'Twas nothing but a jest! Put in all, put in all!

This, of course, is a riff on "is it in yet?", a Georgian take on Lily Allen's Not Fair but popular songs about sexual inadequacy have somehow eluded pop-history. So, what DID Medieval people find funny? We do have several surviving sources. /u/TywinDeVillena talks about the often-rude and sexual humour of Medieval Italians here, and /u/sunagainstgold has an excellent post here that looks.at everything from the satire and smut of Chaucer's Canterbury Tales to the popular humour of Medieval street theatre. I talked a little bit about the Anglo-Saxon fondness for a good dick joke here.