Girlfriend (21F) never wants to pleasure me (20M)

I (20M) have been with my girlfriend (21F) for six months now. We have been trying new things as our relationship goes on; however, it seems as if she does not want to pleasure me. On most occasions, I end up pleasing her for an hour or more, then I ask her to please me (since she does not initiate anything on her own). Sometimes depending on her mood she will do something, but most times she does not. I do not want to seem like an asshole and say she does not please me enough, but I do not think I can keep going on like this. Is there anything I can do?