When you fuck a girl mad hard, then when she's moaning like a wildebeast and cumming, you pull it out and stick it in her ass and continue to fuck her vigorously. Furthermore, she has no time to say "No" or stop you because she's in what we like to call "Pleasure Shock."
1) I was fucking her like i owed her money, til she started cumming and i decided to pull the Switch-Er-Poo on her.
2) Jamie packed her shit and left me because i decided to test out the Switch-Er-Poo on her.
3) Dude, I hooked up with a girl at this party last night and decided to give her the 'ol Switch-Er-Poo.