The result of anal sex if your partner didn't take a dump before hand; the poop straw is that string of feces that tends to get lodged in the urethra during the act, and comes out when squeezed by hand after the act
All that emo girl had for dinner was a Monster and a bag of Hot Cheetos before she gave me the Poop Straw, my penis still burns
The phenomenon of getting feces stuck in the urethra (usually after anal sex with the receiver having a massive turd still in their rectum) and then squeezing said feces out of the urethra like a go-gurt.
Dude, my the poop straw my girlfriend gave me last night burned like hell because of her diet of hot cheetos and salsa.