u-Bob

No, then you'd be violating his property rights. If he agrees to let you kick him in the head, then that's fine. If 2 people voluntarily agree to kick the shit out of each other or to fuck each other in the ass, then no rights are being violated. If one person asks another person to shoot him in the head or give him a lethal injection and the other person agrees to do it, then no rights are being violated.

The Romans used to see 'rights' and 'obligations' as 2 sides of the same coin. You can't have one without the other. Because you own your own body (you have a property right), others have the obligation to respect that property right. Other people can't hit you, harvest your organs or rape you, because then they'd be violating your property right.

When someone does violate that property right, you have the right to act against him because by not fulfilling his obligation to you (by not respecting your property rights), he released you of the obligation to respect his property right. In other words, if he attacked you and tried to kick you, you'd have the right to defend yourself (and if necessary use force to do so) because he initiated an act of aggression. However, you can't just walk up to a random person and kick him because in that case you'd be the one initiating the act of aggression.

I know that most people no longer think in terms of property rights and self ownership... and that's a shame, because ultimately all western legal systems were originally built on those foundations. The foundations are strong, but sadly over time, enormous skyscrapers of legislation have been built on those foundations and today most people are more interested in hiding in the many rooms of those skyscrapers and doing whatever they think they can get away than in respecting their fellow man's boundaries.