People's reactions to this thread confuse me.

My grannie tried to walk in when I was having sex, I was still inside my girl while I answered some questions, then once she left, I resumed sexing.

But never had a full walk-in.

oh god. so i was at my friend's birthday party the other day. it was an outdoor party, and me and this guy guilherme like to fool around sometimes. nothing serious. but we went to the back of the house and hid in a shadowy corner and started making out. eventually, his dick and my boobies were exposed. and everything's just about to get really good when i hear a young voice say, "hey! what are you doing?"
it was my friend's nine-year-old sister.
guilherme tried to hop the fence with his dick still out, and i just ducked and covered.
in retrospect, hilarious.
in the moment, i felt horrible that i'd corrupted the mind of a child. and i still feel horrible.

all i'm gonna say is, make sure you put those 'do not disturb' or whatever those signs are, on your hotel room door when you're getting busy, other the maid WILL walk in in the morning...