Jonathan drinks a little more than half the vial, but only so much. He put the vial back after drinking the watery substance, and Mary stood up to hold the soon to be lizard-man in her grasp. "It took me about thirty minutess or sso for the change to finish up."
His skin started to turn green not even five minutes after, followed soon by a forked tongue and claws. The fifteen minute mark his tail starts to press out and grow thick and heavy. Twenty minutes his head shifts and becomes much like Mary's, while for the next ten minutes his body bulks up and grows larger, straining and ripping his clothes apart.
He appears much larger and muscular than Mary, and with a glint in his eye at the finish, he grins... "Marryyy~ I've got an idea, but firssssst..." He looks into her eyes with his now lizard-like eyes, "You're MY mate now. No one elssessss'. Any objectionssss?"
Mary stares back, a little intimidated, but something close to what one could only describe as instinct made her want him regardless of how he was acting. "I have no objectionss, I'll gladly accsept you asss my mate!"
Jonathan smiled, "That'ssss right... Now..." He goes to the box and pulls out two vials, one marked with the female symbol, the other marked with the male symbol. "By the sssame ssstandardsss, if one of usss were to drink ssso much of one of thessse vialsss opposssite to what we are, we could become hermaphroditic, but that'sss mere theory worth tesssting out." He grins back at Mary, "I have other ideas involving these as well..."