Pitter patter is the firstpart to a saying (pitter patter, let's get at er). It basically means "let's go". This saying is used a lot in the tv show Letterkenny.
Friend 1: You wanna get hammered Friend 2: Sure
Friend 1: Well, Pitter Patter
Friend 2: Let's get at 'er!
Aw brah its just like, you just get the best barrels ever dude. you come in and get spit righttt out. just drop in and smack the lip, wah BAH, just drop back in like BAHHHH, just ride the barrel and get pitted, sooo pitted like THAT.
Alternate: We got super pitted at Jimmy's house last night