I am a girl of 23 but ample behind.Men often fondle my buttocks wnever they have the opertunity.Why I enjoy this and get exited?

Everyone enjoys different things, you enjoy this. There isn't really a specific reason why. Different folks, different strokes, that's it.

Are men you don't know fondling your buttocks or just men you give permission to?

If you have given permission, enjoy the sensations.

If someone takes liberties that he shouldn't, then it may be about more than having your buttocks fondled and may be starting to get into the rush of being on the edge of inappropriate behavior.

Be careful that someone doesn't take advantage and attempt to go farther than you want to go.