I'm new to this bunny owner thing! Hello everyone! I'm new to this sub and to being a rabbit parent. My sister adopted a rabbit about a year and a half ago but due to hardships she asked me to take him in a couple weeks ago. 

His name is Charlie and he is not neutered. Normally he is not aggressive or territorial that I can tell but within the last couple days I've noticed he thumps his back foot a lot and it seems he keeps spinning around trying to scratch his back leg or his butt. Not sure if I'm worrying for nothing or if it's something I can help him with. 

Any advice about bunnies in general would be great. Thanks in advance!