How do I convince my boyfriend to have a threesome?

My boyfriend has an identical twin brother and oh my god they are both so sexy. I used to ship them together and have fantasies about them having gay sex. Last night I had such a good dream that they forced me to have a threesome with them and I enjoyed it so much, I didn't want it to end! And now I'm curious to know what it feels like in real life. I don't know how my boyfriend would react to this, but I'm so in love with him so perhaps this is why I'm attracted to his brother too? How can I get them both to have sex with me?