You've seen your best friend naked or in their underwear at least once, amirite?

I wish

PE

While changing in the gym.

My old best friend used to walk around in his underwear with a throbbing erection it was awk as fuck

My best friend is my boyfriend, so yes.

My male flatmates walk around in their boxers the entire time, they even answer the door to people like that. And I've accidentally flashed my best friend when I was sunbathing and sat up, forgetting I'd undone my bikini top...

I've seen my friend's penis plenty of times... gym class, swimming...penis fights... good times!

I've seen my girl best friend(s) naked and my guy best friend in his underwear.

Locker room...

Psh, I've showered with my best friend :p