My friend set me up wit this guy.....

You should either arrange to see him alone, or give him a call. that will at least show him you're definitely interested. make it casual at the beginning (of the phone convo, or the date) and then say i'm sorry for acting weirdly when we were out with so and so, it's just i get uncomfortable doing things like that in front of people.

if you are always uncomfortable in front of people then leave it at that and he should hopefully understand, but if you become more comfy over time, tell him that it gets better the more you know the person. if he's worth it, he should understand and respect that. good luck!