A guy?

Every morning when I leave for work I tell Sean and Dan, "bye guys". Sean has picked up on that and started saying, "bye guys" when we are leaving somewhere. Anyway, last night Dan said he wanted a kiss from his "baby" and Sean said, "no, baby". Dan said, "well if you aren't a baby, then what are you?". Sean responded, "dye" (guy). Dan and I just laughed. He isn't a baby, or a boy, apparently he is a guy!