A reference to "The Eiffel Tower", the sexual act where one man receives oral from a woman while the other man does her doggystyle. The act wouldn't truely become an Eiffel Tower until to two gents did a double high five.
"I saw Alex the other day, she is such a whore."
"TBTTIPF?"
"LOL"
A bastardization of "for realz", which is a bastardization of "for real". Derriving from internet forums. You'll be hard press to find this "phrase" anywhere else.