A wash and swim is one way of preparing sperm for IVF. The sperm are washed to separate them from the seminal plasma and then placed at the bottom of a tube with a medium (usually in layers of different concentrations) poured on above them. The healthy motile sperm then swim up into the medium and can be removed ready for treatment. It is common for this to be done as a test before treatment to make sure your husband’s ejaculate can be treated in this way.