Phoo-haa they're some big-child-bearing-hips on your boy snake!!!
I bought a 3 year old female at the beginning of this year who had 'hips' due to overfeeding by a previous owner to get her up to weight for breeding. Other than the 'hips' she was in excellent condition. Just like with any other animal, it's not good for them to go on a weight loss diet before you breed them so I forgot about it and figured I'll diet them off her later on....well, she did it for me...after the first clutch they had halved in size and after her double clutch they're pretty much gone. If anything, she just has slightly looser skin around there...then again she had dropped about 60% of her original body weight!
If it's not constipation and you want to get those hips off him, cut his meals back so he gets only one mouse every 2 weeks and once the digestion process has finished, exercise him as often as you can. Let him climb all over the place and whenever you have friends come and visit, let them have the novelty of playing with him...hehehe, that's my trick...my friends actually think I'm letting them play with my snakes for their benefit...they don't realise that they're helping me exercise my animals!!!