the way I seal is this: (and by the way, i'm 3a-b, with fine to medium hair)
After having conditioned in the shower, I rake in my leave-in. Then, I take a dab of coconut oil and smooth in the ends of my hair. After, I apply gel. It works great for me! It keeps the hair from frizzing up at the ends. Also, I've noticed I don't get knots at the ends of my hair when doing this. You should try it!
Ca m'a fait de la pé-peine!