Had this happen. On my old departed guy, when he got way up in years, he had problems with impacted anal glands. The stuff inside was more like cement than the stinky oozy stuff it was supposed to be. He once developed a fissure as a result. Keep it clean till you get to the vet. Warm compresses help. If that's what it is, he'll need antibiotics.
__________________ I still miss my doggies, but now I have Frankie  |