2 year old not playing nice with new baby

Hi folks. My 2 year old son loves his 1 month old little sister. He wants to hold her and hug her, and he tries to share his food and toys with her.Occasionally, however, he gets frustrated that he is not able to play with her as much as he wants, he isn't able to hug mom while she is nursing, you name it. Recently he has started biting her or smacking her. Not hard, but you can see where he bit her and she cries when he does it. When we ask if he bit her he smiles and nods.We have had him apologize to her, give her a hug, and told him very sternly that we don't bite people, he is hurting her, it is making her cry, etc. But then he bites her again a minute later.What can we do to put a swift end to this behavior? He goes to daycare twice a week, and I don't want him to bite a classmate of his. I also don't want him to continue to bite his sister or my wife and I. via /r/Parenting http://ift.tt/2mm5ipU