Tons of sexual tension between me and best friend. What do I

File: Screenshot_2015-11-21-21-35-52.png (2MB, 1080x1920px) Image search: [Google]

2MB, 1080x1920px

Tons of sexual tension between me and best friend. What do I do?

We're both home for the holidays and we've been hanging out a lot as usual, smoked a lot of weed, and now I'm lying awake in one of his needs while he's in another room. There's a ton of sexual tension I'm feeling but I don't know how to act!

>been friends for a long time. Maybe 10 years, I'm now 20
>don't really see him much until senior year of high school
>really hit it off and hang regularly
>we explore drugs together, he shows me the way
>he's very much the dominant one in our relationship
>we progress and eventually think of what the future may be like after college
>both interested in living together and, being very open people, we mentioned how we'd love to be able to hook up and basically be gay but have girls as a side option or a threesome kind of thing
>were both into it but... I have a long term GF I'm not looking to leave
>we kind of lay off the gay stuff for a while and now fast forward to a few weeks ago

>we're both now home for the holidays and I'm with him
>here mentions that our mutual friend, call her A wants to have a threesome with us
>like us she's very open about this kind of thing
>we're both down but we don't really talk about it much
>ever since that conversation I feel tons of tension when we hang out and I just want to suck his cock and kiss him and let him fuck me but I don't know what to do.

I currently have a gf but we've both agreed that we don't care for the sake of having fun (in the context of the three way) but maybe that's what's getting in the way? I think neither of us knows how to break the ice and we're too afraid to lose our friendship.

What do you think?