P.E.N.I.S. - Post Ejaculatory Non-Interest Syndrome.
The post-coital complete lack of interest in the
female companion that engulfs the majority of males as
soon as their
female conquest has brought them to climax
Girl: That was amazing, I love you so much.
(Silence)
Girl: Have you fallen asleep already?
Boy: Nope, just got a bit of P.E.N.I.S.
Don't worry about it.