Uh oh

Okay so I haven't seen my best friend in a while bcuz she's grounded but yesterday was her birthday so I was at her house for a few hours. She has a new bf like they have been dating 3-4 weeks. Her brother told me he was coming to the house later. So I wanted to meet him. I'm really protective of my bestie. Anyway I wasn't really impressed with him. He seemed shy and nice but like his body language and stuff was like weird. Then he wouldn't even talk to my bestfriend. He went a play video games with her brother. Then like he wouldn't quit staring at me or looking me up and down. Then my bestfriend was sitting on the love seat and I was sitting on the couch we were like right next to each other he sits kinda in the middle of the couch by me. I had her brother sit in between us I mean he's dating my bestfriend I'm not gonna have him sit right beside me when he could have sat beside his gf. So anyway she leaves the room to go get something and he reaches behind her brother and starts like poking and touching my side. I was like taken aback. I got up and moved. But he kept trying to be close to me. I don't know what to do. I can't tell her or she might be mad that I don't like him. Here's me and her. 
She's on the left. Sorry if I look bad.