When at a safe altitude line the nose up with a reference point, now bank the airplane in either direction but use just enough rudder to keep the nose of the aircraft pointing at the reference. Now slowly remove the aileron input towards the other direction while slowly removing rudder and applying opposite rudder as needed to do the same.
This will get you comfortable with the sideward forces and awkwardness of the forward slip. It may also improve your crosswind technique. I believe these are called "dutch rolls."