Newly neutered kitten licking his penis?

I had both of my kittens neutered on the same day, a week ago, and within a few days they were both playing like normal. 

One thing that is troubling me is that one of them licks his penis. I'll catch him legs spread wide, sitting on his tail, lick his penis. If I stop him, he'll stop and get up and do something else. He'll play with no problem, uses the litterbox no problem (twice a day for each number 1 and number 2, same as before), he eats no problem... I feed them both wellness dry and canned kitten formula. Dry food in the morning, wet food at night. 

Both of them drink a lot of water... 

I'm thinking I will take him to the vet tomorrow. 

Anyone have any experience with this?

Could it be related that they wouldn't take a few days to recover? They were running around and chasing each other the day after their surgery. I tried to keep them relaxed and separate from each other, but it did not work. 

The other cat is fine. He doesn't really lick himself at all and his area also looks like it's recovered just fine. 

How does he look in that area? Is it red or swollen or anything? If it is, call the vet as soon as you can. If not, it may be that he's just more sensitive than his brother and the incision may be itching as it heals. Unless the licking seems excessive or obsessive it's most likely normal. And since he quits when you get up it's probably not too bad. Males don't really need a few days to recuperate. . .it's just a flesh wound, no internal surgery or anything.

The licking of penis as such isnt nothing especial. They like to keep it clean.  And sometimes you can even detect some amount of pleasure connected in there somewhere. They can feks licks themselves shortly after some common cuddling or even talking friendly to them...  

So, licking of the intime parts, if not very too much, is pretty normal.

The problem HERE may be if it is connected with the surgery.  It is penis or the sacks he is licking?  How is it looking?  Well healing wounds or you see something not so good?  The wound can look as a bit of fur missing, you seeing something pale...  If it is healthy and more or less pale, its OK, if it is inflammed and red - not good.

If you hesitate - call the vet. They are his patients, so every vet will answer telephone questions, even the vets who usually are reluctant to telephone advices.

Good luck!

I can't add much here but I have to agree that if it is inflamed or swollen it might be best to contact the vet.  My cats like to clean themselves often and Ramsey did lick himself more than usual at the outset after neutering.  He stopped after awhile so I wasn't too concerned.  There were no signs that he had contracted an infection ie: swelling, redness etc. so I did not take him to the vet.