When someone brings too much attention to something that you may be wanting to keep on the low. So much so, that they may get you caught and or in trouble.
That dude over there's the fool who was blowin up my spot last night. Because of him my girl knew I was out with another girl last night.
A plastic air filled doll for someone to have sexual intercourse/anal sex with or receive a blowjob from.
Chad : Oh Kiersten you don't know how much I would love to smell your hair, caress your breast's, stick your mouth around my dick and pound your pussy once again!
Kiersten : Why don't you just get a Blow Up Doll and leave me alone!
Chad : I would but the wifey don't want the extra company in our bed!
Kiersten : You are fucked in the head get some help!
Steve : Hey guy's like my new Blow Up Doll her name is Judy!
Chad : And you think I'm fucked in the head?
Kiersten : Ok I'm sorry you and Steve are fucked in the head!
Short-hand for the word floccinaucinihilipilification, meaning the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language).