Kitten's bottom problems!

Sorry, this may be a bit gross....

Lily seems to constantly have litter stuck to her anus. Tonight, she stuck her bottom in my face when we were playing and there was a big chunk there, so I decided to help her.

I wet some paper towel with warm water, and got DH to scruff her while I cleaned her bottom. She squirmed until I started, then she stopped squirming and let me clean it - like she knew what I was doing and was happy to let me. Either that or she was grossed out and felt violated and figured it wasn't worth fighting

Anyway, so just wiping didn't do much, so I carefully used a fingernail to pry it loose, and it looked kind of swollen underneath and a darker pink than the rest of her little bottom. Once the big bit was loose, I was able to get the smaller bits off with the paper towel.

I gave her some Gerber baby food as a treat for being so good, and still thought she would race off when we put her down, but she just went back under the table, and lay down dear DH's feet.

I really think she appreciated it...

So, why would she be getting it stuck there? Is she sitting in her litter to do this? Is it a problem that it's getting stuck? Will she learn to clean herself properly as she gets older (she's almost 4 months)? Should I be "helping" her when I notice big pieces stuck there?

I also have a four month old kitten that has somewhat the same problem. I have heard of other people clipping the hair back there, but this is something I do not want to do. This is the place that I brush carefully every morning and I have changed my cat litter to Petsco Gold and this has helped. The changing of the litter caused no problems. I do not know what other kittens do but mine (male) squats right in the sand to pee so obviously some of it is going to stick in that area.

She's got short hair, so it's not a coat problem. Just a lack of cleaning herself problem! If I was her, I wouldn't want to lick it off either