2. Simply extract the anxiety from sexual performance:
People usually think of sex as this is something they should be doing so well. But instead of this, it should be treated as something one enjoys, and feels absolutely unpressured about. Like everything needs a little warming up session, sex too needs this. If you have that session before sex, you will less likely to think about performance at bed and you will easily get into it.
If someone loves to play guitar, right before playing, just close your eyes and feel the slow rhythm of guitar and now start diverting the attention and relaxation to making love to your partner. This will help you reduce the anxiety.