Rear-entry is a sexual position where one partner penetrates the other from behind. This position can be performed in various ways, such as with one partner on all fours or lying flat. It allows for deeper penetration and can be adjusted for comfort and pleasure. This position is often associated with doggy style, but it can also be adapted for other scenarios, such as using a bed or couch. Rear-entry can enhance intimacy and provide different angles for stimulation, making it a popular choice among couples exploring their sexual experiences.