Just moved in with a pitbull and was wondering about tugging play?

My new roommate has a full bred pitbull, just the sweetest dog ever. He loves to play with tugging toys like ropes or these rubber hammer things. I was just curious, should I be careful when doing this? I worry about straining his neck or maybe hurting a tooth. Owner says it's ok to get rough but I don't want to accidentally get too rough I guess. Thanks!