Being un-cool or rude to someone.
Everything was going great, until Becky came in being all bumpy.
is the act of giving someone such head on a couch it literally bounces up and down
guy: hey dude my girl vanessa gave me super hard slumpy bumpy couchy ouchy that there are now marks on the floor!!!!1!1!
other guy: who is named vanessa nowadays
its somewhere between "dump truck ass" and "cutie booty"
"her ass was ok, it was more like a dumpy bumpy. Just under a dump crump lump"
Slang used to describe sexual activity involving oneself's anal cavity especially if the receiver is rather large from behind. Typically the posterior-end is referred to as "dumpy" which is due to roots within the word "Dumptruck" (which is a vehicle commonly used to haul large quantities of sediment from one location to another), and the word "bumpy" being used to describe the motion of anal sex where one bounces off of their partner.
Man! Me and your sister got it on last night. We did the dumpy bumpy so many times!
When two people have sex.
Do you want to have bumpy cuddles?
When your girlfriend is snuggling on top of you and it turns into sex.
She wanted to snuggle but it turned into snuggle bumpies.