Question: At 12:07 is it the shower or the toilet that makes a weird draining noise? Almost what does he look at that makes him vomit? (00:12:07)
Question: When Malcolm leaves the bathroom after Big Momma gets in the shower, does the toilet or the shower make that weird noise? Also, what is he looking at that makes him vomit?
Answer: I think it's the toilet unclogging. Also, he was probably looking at the diarrhoea she left behind in the toilet bowl.
Answer: The "draining noises" are Big Momma taking a dump. Big Momma didn't flush either so I'm assuming he took a look at her stools and what he saw made him feel sick.