So dogs like that area to be scratched because that part is hard for them to reach when they groom, so when you pet there they are like “YES! BUM SCRATCHES!” Cats are similar, but because their tail is more developed than a dogs (since they use it for balance/control) there are A LOT of nerves at the base of the tail, so it’s a really sensitive spot (think of it like your neck, it’s a strong reaction when someone tickles your neck). And when a female cat is in heat they arch their backs and “present” themselves so that might be another reason for his sensitivity near his bum.
(⊙…⊙ ) i’m sorry.. i got too into writing this! I’m a biology/zoology major so i get way too involved in writing animal facts!
Do real cats actually get aroused when the base of their tail is touched? I’ve never owned a cat but my dog really likes it and he will constantly reposition himself in order to get that sweet spot scratched... ( ̄∇ ̄")