Dark spot near base of the tail

[Prichtofu]

So my veiled was sitting on my desk yesterday hanging out on a vine, and he pooped on my desk, which was whatever, but after he did I noticed this dark spot appeared, and has been there since. I've attached pictures. Is this just poop that can be washed off or is it something else? He doesn't show any discomfort when touched (other than normal reactions to me touching his butt). I'm thinking it is just poop because he was at kind of a weird angle when he pooped from the vine.

 

[jannb]

Wet a Q-tip with warm water and see if you can wipe it off.

 

[Prichtofu]

Wet a Q-tip with warm water and see if you can wipe it off.

It was poop. I'm dumb.