Women are kind of lucky when it comes to bedroom activities. If they don't feel like working for it, they don't have to. And they know you'll have a pretty good time anyway, even if it is just you putting in most of the physical effort. However, a woman who is in love with you will want to get totally into it with you and be an equal participant.
You won't find her just laying on her back letting you do all of the heavy lifting (sometimes literally!). She wants to please you and make sure you have an amazing sexual experience with her. When you love someone, it's doesn't even feel like hard work. You just genuinely want to do it. So, sit back and enjoy the ride, because that's what she wants you to do!