MrL Some genres are also have more of these than others. For example, sex comedies and are at least C grade (the American Pie films are grade B on average imo). I’d add some films from horror subgenres, but the horror element usually ruins it for me.
The first “American Pie” (1999) film has not only B-grade navel exposure, but actually has the protagonist run his hand down a cute exchange student’s (Nadia) bare stomach (Nadia is played by Shannon Elizabeth in her mid-20s).
To cite a good example from the horror subgenres, the horror comedy “Tucker and Dale vs Evil” (2010) gets an A. Not only are there a few bikini scenes, but one woman, Allison, gets a change of outfit after being saved from drowning, deliberately ties the shirt up to turn it into a crop top AND keeps it that way for the rest of the film (and she’s played by Katrina Bowden in her prime). Allison alone earns the film an A.
I rank American Pie below Tucker and Dale vs Evil because while American Pie has greater quality, Tucker and Dale vs Evil has good quality and great quantity.