About two weeks ago, I acquired a pretty underfed male BCI (who is allegedly three years old and skinnier and no longer than my year old male ball python). While feeding him (one small mouse about the width of his thickest point, I don't dare feed anything bigger) yesterday, I noticed as he had his mouth around the mouse, there was a black spot that appeared to be on the glottis. There was no pus, redness, or other abnormalities I could see, but this was only briefly.

I was wondering-- is this a spot of pigment, or a possible sign of disease? How could I open his mouth and take a closer look with it being the least stressful towards him?