The missionary position with anus penetration is a variation of the classic missionary position, where the person in the receiving position lies on their back with legs spread and bent. This variation includes penetration of the anus, which can provide pleasure and stimulation for both giver and receiver. It's important to use plenty of lube and take it slowly to ensure comfort and pleasure for both partners. This sex position can contribute to intimacy and immersion in sexual experiences, but it's important to trust your partner and listen to your body signals throughout the act.