To answere your question why? Well you only live once so you may as well enjoy every experience that
is presented to you,would a man be able to tell the difference if during group sex he was blindfolded,
was recieving blowjobs from women and a guy starts sucking him off,would he be able to tell or would he really care?

Why not? Well for a straight guy to even brush against another guys bits is freaky,let alone get a blowjob.
I think it would leave mental scars for life,so that alone is reason enough not to.