Vibrators && Pregnancy?

I posted a question similar to this earlier, but I want more advice. I am currently 33 weeks pregnant, and on bed rest. The doctors never said anything about not having , but my boyfriend wont because hes afraid he'll hurt me or the baby. He will use his fingers, and the vibrator though (sorry if TMI). My question is, if he sticks it in, on the highest setting, can that cause my water to break? Like the vibrations or something? I dont want to do anything thats going to harm the baby, but the doctors never said anything about it. I know I can call and ask, but no matter what doctor it is, its still embarring. Just wanted to get some opinions. Thanks in advance! (: