"Well Princess, if a man ejaculates in your presence with your permission, consent, or active participation, you just had sex."
If your son says something similar the slight variation is "did you ejaculate in the presence of...etc
Insertion Exemption: Any consensual insertion of penis or penis like object into a bodily oriface can qualify as sex too.
Wife: "You What!!!!!!?"
Man: "Its OK, Urban Dictionary says the Urban Dictionary says that this doesn't qualify as the Definition of Sex"
Daughter: "I'm still a virgin cause I have my cherry. I only let my boyfriend ass hump me
Father: "You are one sick pup, Princess"