If he gets mad doing it take some Vaseline and keep applying it to he area.
They hate the feeling on their fur and it makes them clean themselves and it
is safe for the digestive system.  While the wipes have harsh chemicals in
them

How long have you had cats ?  When I first got cats I seemed to take them to the vet for
everything !!

I remember when I first got Margie she used to lay on floor and pull herself with her
front paws.  I got freaked out and thought she could not walk and rushed her to the animal
ER and it cost me almost $600 for xrays and meds and such and everything showed normal.
They said it was most likely a "Soft tissue injury" and to take her to my vet.

Dr Tina ( http://vethealthcenter.com/ ) looked at her and said their was nothing wrong and
that most cats pull themselves like that at times.  Well I watched the other 3 and she was
right.  They all do it one way or another.

In the 8 years since my babies adopted me I learned not to jump every time they sneeze or
get a runny nose or such.  But if it continues then they go to the vet.

My furbabies

http://users.ameritech.net/lestark/

I have one who sometimes wipes her bum on the carpet when she's done; she's
been doing it for years so I'm used to it;  maybe your's is going to a
"wiper" too.  Not much you can do about it except catch him when he gets out
the box before he can wipe it on something.  Don't use wipes though (they may
have chemicals on them).  Just wet a paper towel with warm water, squeeze it
out and use that.  Don't rub, just blot.
If you notice his poop is runny for days, then call vet.

My 3 year old male cat has the same or similar issue. I notice that he
doesn't groom himself very well. But, then, he never has been great at
grooming himself  "down there." I also use baby wipes when necessary, but
only to keep him clean. He doesn't leave spots anywhere he sits. I believe
that he's a poor groomer in part because he was only around his siblings and
mom for about 8 weeks. Maybe he was the kind of kitten that needed the extra
4 weeks (12 total) that vets say is optimal for kitten growth and learning,
in order to learn proper hygiene. It may also be due to his personality;
maybe he's just not that big of a groomer. So, for me, it's always just been
an issue of the way he is. But, based on what you've said, I think you
should check your cat out. First, because his grooming has changed. Since
there is a change in behavior, that's enough to suggest something may be
causing this problem. Also, your cat is using the box more often, that's
another change. Two new behaviors suggest to me that you should see the vet.
Have him checked out just to be on the safe side. You'd hate to find out
later on that you were given early warning signs to something easily
diagnosed and fixed only to have it become much worse over time. Good luck.