" is group sex sharing ....?"
If an app is involved, you'll be unknowingly sharing everything with anyone and everyone that wants your data. At a minimum you'll be "sharing" your erection length, girth, firmness, length of stroke, number of strokes, semen volume (if you ejaculate), sounds you both make, position preferences, dirty talk, toys used, lube viscosity and flavor, post coital cuddling or lack of such, video captures of your activities, still photos of your O-face (ahegao), and who farted during and or after. You will then receive lifetime supply of unwantted advertisements for boner pills and gym memberships.
And your children and their children will be able to "share" that permanently archived personal data through a simple AI conducted search and animate your activities to share at family gatherings. Such Fun!
Sharing in 2025 isn't just a quick threesome anymore.