Well, without a clearer photo it is really hard to tell. It is completely normal for there to be a strip of smegma (sperm plug) hanging out of a male's vent occasionally. You want them to shed this, and normally it comes out with a poo and the cham wipes it off onto a branch. Sometimes it gets hung up there, though. Smegma colors run from creamy white to light brown. So, it could be that. The only other alternative I know of would be an adult parasite of some kind.
Coincidently, I carefully pulled a hemipene plug from my Veiled just today! I could see that there was something keeping his vent slightly open on one side. I was able to catch a tiny edge of it and while gently pulling, it slowly came out. It was only about 3/4"-1" long. Whether he needed my help or not, it looked uncomfortable . I didn't see another one from the other side ready to come out and I hope there isn't one there still hidden .
The darkest end was what was slightly visible at the vent.
Photo taken on white tissue (4hr dried-out):
Photo taken on blue paper (and plug turned over and about 1/2hr more dried-out):