Used first by the lovely Nimz to describe awesomeness related to video game personality Stuttering Craig's website - screwattack.
Anything that is awesome, fun, fresh, and/or original.
I'm having a screwsome day, now that I'm finally finished with work.
A couple (MF FF or MF) who regularly hook up with other people for three way sex.
He was lucky enough to find a screwsome that wanted to hook up every weekend.