Hell no. I like to keep the women things to the women. Dudes get pulled into this by women. Understand this if you're getting asked by a hot piece of ass to get your nails done with her - it's okay to say 'no'. This is the same as if you're going to play cards with your buddies and you ask her to go. She has the right to say no. In fact, it is healthy. She doesn't need to go to card night. She likely doesn't care. By going, she isn't showing an interest in your hobbies.
Don't get a manicure if you're a guy. Keep them clipped, wash your hands, and clean the dirt from your nails. But leave the manicure to the ladies. There are certain things that should still be for the guys and for the ladies in a relationship. And this is one of them.