Dad looking like Kate Upton

"... Kate Upton! A naked Kate Upton!".

"Son...", the apparent nude swimsuit model started in Walters male voice, "Remember it's still me in there! And I just look the part, I don't sound like it. So don't get too excited!"

Just then, 'Kate' AKA Walter looked down at her sons crotch where she was surprised to see a rising boner.
"Jacob, is this a banana in your pocket or are you just excited to see me?"