One of my butt cheeks is larger than the other. It's not VERY noticeable, but to me it is because It's MY BODY and when I clench my butt you can feel the difference.

Should I focus on one cheek?

If I work out just my big cheek will it get smaller and toned, or will it get bigger and muscular?

If I work out just my small cheek will it get smaller and more toned, or will it get big and muscular?

Please only comment if you have an answer for my problem,

Thank you

Work the smaller one harder. It's normal to be slightly one sided. Most people automatically start walking with a particular foot, and always jump from the same foot, so one leg, and the muscles in it will get worked harder than the other. So the glutes on that side will get slightly bigger. Unless you are very one-sided, it's unlikely that anyone else will notice, but the answer is to do extra work with the other one to bring them into balance.

Note, the glutes are huge muscles, you have to work them very hard to make a difference. Clenching won't do it. Try one legged romanian deadlifts, step ups and lunges.