Show them your manhood as an explaination...

“There’s nothing weird about this” You tell the three girls, “They’re not just my family, they’re women too.”

The slim blonde, Lindsay scoffs at this and her two friends look at repulsed at what you’re saying but instead of arguing further, you unzip your fly and pull out your dick. Your mothers and sisters look shocked at you and the girls gasp in alarm as they see what you’re doing. Up until now all you had been doing is looking at and petting your family members, but you decide that it’s time to take it further. The girls all look down into your lap and their eyes widen as you command your normally average dick to grow.

It lengthens and thickens noticeably, until it has doubled in girth and sits ten inches long in a flaccid state. Britney’s mouth moves wordlessly while your younger sister Jessica and Mother sit motionless entranced by the sight of it. The effect of Lindsay and her friends is gratifying; Lindsay has been silenced by the sight of it and turned red again, Athena, the brunette, stares at it hungrily, wetting her lips gently and Sophie peeks from behind her hands as she tries to cover her face in embarrassment but can’t resist gazing at your new, now monstrous, manhood.

“Oh my God,” Athena whispers, barely audible over the music, “You put that huge thing in them?”

“No,” You reply “I haven’t but I probably will soon, after all, tonight I’m celebrating a lot of things…”

You sisters and mother look at with a mixture of both horror and anticipation. Suddenly aware of their nakedness again and your intentions, they begin to cover themselves with their hands, forcing you to sooth them again with your new mind powers. Sophie finally speaks again;

“A man with a dick like that could…” she trails off “John, can I touch it?”

The rest of the girls turn as one and stare at her in astonishment….