What do I do?

So I have this friend, who's a guy, the brother of my BFF. he's started acting more touchy with me lately, massages, laying next to me or on top of me, picking me up and carrying me bridal style into a room. Last time I was over there we were watching a movie, he asked for a massage so I said sure and gave him a back rub for about 10 minutes. He said that was good and asked if I wanted one so I said sure. I layed down on my stomach and let him rub my neck and back, he worked lower and lower until he was at my thighs and he worked down my legs and to my feet and then back up to my upper thighs and to my butt. I didn't really care that much so I didn't say anything and he kept massaging me there and in my inner upper thighs. The movie ended and he went to take his shower and came out in just a towel around his waist, went to his room changed into sweatpants and came out shirtless again. And then sat down on his phone as I talked with his sister who was there the whole time he was giving me a massage and gave me a well deserved look and then preceded to whisper "OoOoh! He touched your butt!" And laughed. The next day we were fine he said good morning and I did the same. Idk. I'm just confused. Anyone have any input? Suggestions? TYIA!