Sometimes known as stuffing rope, or stuffing the marshmallow, the art of flumping is one whereby a male consumes too much alcohol, resulting in his penis resembling that of a marshmallow. He then proceeds to try and fold and push it into the woman's vagina - unsuccessfully.
Eliot - hey man, where'd you go last night?
Stu - went back with that girl.
Eliot - sweet, good night?
Stu - yeah, ended up flumping for 3 hours.