When your penis becomes erect when talking to a girl, but not because you're horny or want to have sex. Its an erection caused by the good feelings of having a conversation with the girl.
I really like her, but I don't think of her in a horny kind of way. When I talk to her, I get an affection erection.
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).