This goes back to Ancient Rome, where the alpha male was supposed to be the penetrator at all times, never the penetrated. He could engage in sex with men or women as he pleased, but never could he be a fellator or paedicatus. That's why Catullus's 16th poem, which begins "Pedicabo ego vos et irrumabo" (I will fuck you in the ass and in the mouth - irrumare is the mirror verb to fellare, the act of shoving one's cock in someone else's mouth), is considered to be such a violent phrase. Therefore, if something "sucks", it means it is in a subordinate position. It's not really tied to homosexuality or heterosexuality per se.
ἡ δὲ κἀκ τριῶν τρυπημάτων ἐργαζομένη ἐνεκάλει τῇ φύσει, δυσφορουμένη, ὅτι δὴ μὴ καὶ τοὺς τιτθοὺς αὐτῇ εὐρύτερον ἢ νῦν εἰσι τρυπώη, ὅπως καὶ ἄλλην ἐνταῦθα μίξιν ἐπιτεχνᾶσθαι δυνατὴ εἴη. – Procopius
Ummaka qinnassa nīk!
*MySmiley*