Head expansion

Lately I have noticed that the head of my penis hasn’t been expanding like I know it can, it barely expands when I get those random erections and doesn’t expand much when clamping. When I jelq it gets nice and full but besides that it doesn’t expand much, I haven’t had sex in a couple months so I can’t compare it to its state before sex. When I do masturbate I rub the head instead of stroking (better feeling IMO) do you think that could be contributing to this problem?

Thanks for any replies..

IMHO, rubbing the head should actually help expanding it……