Giving or receiving?
Giving - Focus on the fact that you're pleasuring your partner. Think about how much they're enjoying it. Sometimes separating yourself from the action and only focusing on what your partner might be feeling is great! Try a flavored lube, use a toy. Connect with your partner and ask what they want.
Receiving - Relax. Try to keep in mind that your partner is wanting to take care of you! It's their desire to make you feel good. That's amazing! If it helps, turn the lights off, close your eyes, and simply focus on the feeling. Don't worry about how you look, don't worry about what they're thinking. Allow yourself to just feel the pleasure.