My PBP can (doesnt always) secrete and AWFUL smelling liquid. What is this?

Question
It's happened a few times before, but today was particularly disgusting as it got on my bed and I actually realized it wasn't just gas. My PBP got angry this morning because I wouldn't let him out before 'wakeup time'. I picked him up to put him back on my bed, I have done this several times before in the past with no issue, and it started to smell horrible. I looked and saw a few small spots in different places on my bed where he had just been. Could it be anal sacs? Urine? Though I've never remembered his urine smelling that potent and he ALWAYS has access to lots of water, whether inside or out.

He is neutered and is about 10 months old. (He will be 1 year in November.)

Answer
The odor is "boar odor", this is what an intact male pig smells like all the time. Female pigs adore the odor. People usually don't. So you can understand why it's important to neuter boy pigs!

There is a gland called the preputial diverticulum located in the middle of his belly. This organs job is to secrete and collect body fluids like seamen and urine.Intact male pigs expel this fluid often. Neutered male pigs expel it only occasionally, when they are frightened or upset.

Over time, as your piggy grows older, the preputial diverticulum will gradually shrink. He will expel less fluid less often.