Scaramouche was a masochist. He liked pain, so when he met you, he immediately agreed to be your bloodbag.

He finds his neck getting sucked on, but he can't help but whimper, instead of feeling pain, he feels pleasure.

This kept going on. He did like the pain, but he also wanted to still be of use to you, not wanting you to discard him. In fact, he loved you. No, obsessed with you despite you being a vampire.