It is safe to use fingers or not?

I had a baby two and half weeks ago, obviously we can't have sex but man we are so ready for it! I've been giving oral sex to my husband and using my hand, he wanted to use his fingers on me but I said no, finally I said yes because I really wanted, he's been doing that for the last three days, he read that is safe to do it, how true it's that? Does anyone else does this before the six weeks are over? I stopped bleeding five days after I had our daughter and I didn't had any pain after delivery.