actually, i think i just needed to understand how the system worked a little bit better. i went to university for a long time, but i'm not a plumber, and i don't actually know anything about plumbing. but that's how you learn, right.

so, there's a p-trap beside the cleanout (i think i said dugout previously) and apparently it can evaporate, thereby releasing sewer gas. and, the guy upstairs likes it cold and dry, so he was no doubt running a dehumidifier down here. and, i like it hot, at least, even if i'm struggling with the dry air. so, the conditions for evaporation were present.

what you're supposed to do is fill it up with water, so i untaped it and then i did that.

but, then i taped it back up again to try and lock the moisture in. maybe i can put a ziplock bag over it or something; crazy glue the tupperware.

i still need to lysol the fuck out of it. and we'll see if it even works or not. but this at least makes sense.

then, why did running the water stop the smell? i guess it must have been blocking the gas from coming back up the trap.

if it works, i'm probably at least mostly right.