Getting bruised while having intense sex.
Men and Women both get caught up in the moment and excitement and of course black and blues may occur. A woman for example, may receive black and blues on her thighs/hips where being tightly held by a man during intercourse. A man for example, may have bruises or scratches on his back from a woman digging her nails into his back when she's coming. Such bruises are 'screw scars.'