Well, what I would do is I would wait until he came back. When he came back and he was like "Huh?", I'd be all like, "Hey, sorry, I came back because I forgot something." Then as he opened the door I'd rush infront of him, pick up the bag of poo, go into the bedroom like I lost something in there (more logical) and then shove the poo in my purse and walk out and be like "Found it, I better get going, I left my number, okay bye!"
But still, the place would smell all shitty.
The toilet whould still be broken... I whould have kicked/Axed/blown down the door to take the bag of shit, or **** it, after recking the door i might as well leave it just for fun. It's not uncommon for crack heads to take a dump after a break in. I whould'nt be prime suspect ya'know.
Yeah that whould have been the smart thing, and I can't see myself getting in a situation like that to start with. But if i had locked in my shit at a girls apartment, i... Probably whould have left it and felt proud. I mean, the look on whatever girl/guys face, when they come home to find the person they they just spent the night with fecis on the counter with a note next to it, whould be priceless. And just imagining it and retelling it for your friends whould be epic.