7 minutes in the movie, we see Josh O'Connor's butt as well as Harry Lister Smith's butt as Josh O'Connor is sodomizing him.

29 minutes in the movie, we briefly see Alec Secareanu's butt as he washing himself.

35 minutes in the movie, Josh O'Connor and Alec Secareanu are both naked. In particular we get a good view at Josh O'Connor's hairy butt crack.