Both my Biewers (male) do this. My female Yorkie does not. When I spoke to my Vet about it (fecal tests were done) she told me sometimes they do this for the same reason we use toilet paper.
I know....it sounds gross. But sometimes it just is what it is. Either way, taking him to your Vet is always the first decision you should make. You'll know soon enough! I hope everything works out ok.
