This is just a thing no one needs.
Unless you truly want to be “that guy” we don’t recommend this. For one thing, it could make checking your phone on the train in the morning a criminal offense. Also, phones are kind of dirty, actually. Probably more dirty than your penis, so for health reasons we can’t condone this behavior. We also can’t stop you from doing it, we can simply offer these warnings, and then refuse to pay your bail money.
This might seem obvious.
We’d imagine if your in a position to want to slap someone’s nipple, this is probably your stated goal anyway. So it seems like all we’re offering you here is some scientific confirmation. But don’t try this at home, unless it’s on yourself, or a fellow consenting adult. This isn’t the kind of ice breaker you want to bring to your next dinner party. Unless you hate being invited to dinner parties.