anyfuckingwhen

The combination of the words "fuck" and "anywhen" which implies somebody's strong interest into sealing a deal very quickly.

The abridged version "anyf'nwhen" can also be used.

Hot chick: I wanna suck your cock baby...
Horny dude: ANYF'NWHEN!

Dude1: Dude, it's been forever since last time we meet, we should hook up for a beer somewhen, what do you say?
Dude2: Totally dude, i'm free anyfuckingwhen!