It's hard to be sure that he did his own nude scenes. He gave interviews at the time where he said it was a body double but later, he said that it was him in the scenes and he said that he lied to keep his wife (Patrick's mother) from knowing that he did nude scenes and sex scenes in those movies.
So, who knows if those pics are him or his body double.
It's not being gay that gives them a big butt however, gay men hogging the damned leg and ass machines at the gym might have something to do with it.
Not sure if you're being sarcastic because of the dick prosthetic posts in this thread.
Patrick did give interviews where he said he is nude and the ass is his ass (and given the discussion about how flat it is, that does make it more likely to be his ass).
Notable: in the interviews, Patrick didn't say that the dick was his.
Gay men have always liked ass. Ass and Judy Garland.
But this out-of-proportion jiggly ass thing really got supercharged with twerkers and the Kardashians. It used to be that we liked a firm shapely proportionate ass.
These days, looking at OnlyFans is like looking at a jello mold fruit salad in a 1970s public school cafeteria meal.
For the record, Patrick's ass is just fine as it is.