Oh they have definitely fucked girls together...there is no way that they are that comfortable with each other bodies unless they have been very intimate...maybe they have DPed girls together and maybe jerked off together.....i can personally attest to that because it happened to me and my friend...i am bi and my friend is straight although bi-curious...we had threesomes together and we fucked a girl together in her pussy and after that when guys orgasm together and sleep together, you grow way way closer....before that we used to be shy and after that we have no shame being naked around each other and when we go to swim in rivers we are always naked and jerked off together too.....and we have done more threesomes too and msny times we looked into each other eyes when we were cumming when our dicks were rubbing inside the girls pussy....and many times when i wake up i find us cuddling together with our dicks touching and sometimes spooning with each other dicks near others asses and hands on each other pubes....there is a wonderful intimacy in that and even though we havent fucked and nor do i intend to it feels nice,.....and i feel they are that same way