An appropriate response to every and any situation. Originally derived from the the bepis/conk birdmeme, it's use has expanded to its current situation given the word's similarity in sound to the word for a man's genitals.
Kevin: Hey, how are you doing. Do you want to go out tonight?
Nick: Bepis!
Mr. Moon: have you guys heard of new this chicken place in town? We should go Nick: Bepis!
Joe: Sorry guys, my mom just died, so I will be absent for some time.
Distorted version of the word penis. Became popular in 2011 as a mispronuciation of the word penis, then used again in popularity in the game undertake.
She thought she saw you wearing a bepis, is that true are you wearing a bepis. -Sans in Undertale