I'm wondering just how many times we've seen Wolvie actually draw blood by using his claws on anyone who is, or used to be, a fellow member of the X-Men.
I'll just mention a couple of fairly recent examples, to start the ball rolling.
1. He killed Jean Grey with his claws in "New X-Men #148." It was supposed to be a mercy killing to keep her from roasting the way he was about to as the asteroid they were on plunged toward the sun. (Naturally, she made a fast recovery.)
2. He clawed Jean over and over and over again in "Phoenix: Endsong," because she specifically asked him to do so, for her own good!
I can think of at least a couple of other times, but I'll shut up now and let someone else participate! :)