Call her out (Overt)

You decide to claim that you know that only Futas can get the condition "I know that only people with the condition are Futas"

Your mom stops and sits back down and smirks at you "While true, THAT isn't common knowledge after all. Government wanted awareness of the condition, people wouldn't care if only a small percentage of people could actually get it" Seems she called you out instead

She keeps her smirk at you as she says "Well I wonder how you found out about it. Well since you already know I shall have Ellie use her mouth on me" She eyes you a bit then continues as you see her cock now exposed from under the table and fully hard it must be at least 12 inches to poke above the table "Ellie dear come here just like before this time we will finish though"

(A/N: Just your mom enjoying your Girlfriend and doesn't care if you see)