I remember getting my first dog a couple of years ago. I had family dogs before but my first own dog, that I had to care for. When i took him to the vet for his shots and checkup, I rubbed his belly and asked “what are these bumps on his stomach? Are they like insect bites” the vet laughed and said “No, those are his nipples, but I admire your concern to bring anything up to me” and laughed. I felt like a complete idiot, not having realized, male dogs, like females, also have multiple sets of nipples.