Mucus or pus coming from the anus and coating stool is clear evidence of irritation, probably due to an infection, inside your rectum. Gonorrhea, chlamydia, and other STDs cause such symptoms, but those are unlikely based on your sexual history. (Anal warts are common in men who have not had anal sex, but gonorrhea and other STDs are not -- and fingering doesn't count as a risk.) Internal warts don't usually cause such a problem, but could do so if internal warts are quite large, either directly or because such warts can predispose to infection due to common rectal bacteria.
This is not something to mess around with; you should be medically evaluated right away. STD clinics are experienced in evaluating such problems, but since standard STDs are unlikely, there is a high chance they would only be able to test for those things and then refer you to another provider. Your best bet is to locate a proctologist (rectum specialist), which should be pretty easy if you live in a major metropolitan area; otherwise seek out a surgeon with particular experience in colon and rectal diseases. You could phone your county medical society to find someone; or call the STD clinic, which most likely could tell you which proctologists or colon/rectal surgeons to whom they refer patients with such problem.
Please come back with a follow-up after you are evaluated and report what was found.
Good luck-- HHH, MD
Since I posted my question, I have seen two colon and rectal surgeons.
The first doctor I saw used a little camera to look inside my anal canal. He said he saw a tiny wart and that my anal canal was inflamed and said it may be proctitis. He told me to supplement my diet with metamucil and check back with him in two weeks. He said he may want to perform a colonoscopy to see how far up the irritation is. This doctor also performed an anal culture test to check for chlamydia and gonorrhea. The lab results were negative, or unconfirmed.
Today, I saw the second dr. In my opinion, this doctor seemed a bit more knowledgeable and took the time to ask me a long series of questions about my history. He performed a digital exam and inserted the tiny instrument that the first doctor used as well. He said he saw no warts, blood or other serious signs. He said my hemorrhoids were rather large, but that they probably wouldn't need surgery. He also suggested I supplement my diet with metamucil and that I should see him again in a month.
I recently also had tests for HIV, syphilis, gonorrhea and chlamydia, all of which were negative.
Is there anything that sticks out to you from what I've told you here? Is there anything you think I should tell or ask the doctor next time I see him?
Again, thanks for your advice. I believe your suggesting to see the doctor was the catalyst that pushed me to get the medical attention I needed.
It sounds like you are under good care by a knowledgeable professional, at least the second doctor. I'm glad you sought expert care and that the forum apparently made a difference. But more important, I am glad athat nothing serious apparently was found. Nothing special stands out. Continue to follow your (second) doctor's advice.
Take care-- HHH, MD