"To lose altitude quickly by slipping, should you slip to the left or right?" - Carol Z.
“To answer this, you need to consider whether there’s a crosswind, particularly if you are lining up on final approach.
If there’s a crosswind, slip with the wing down into the wind. This will prevent or limit the effects of the crosswind and tend to hold you in position on the final. Slipping with the wing down away from the wind will magnify the effects of the crosswind and require that you line the aircraft up again after coming out of the slip.
Other considerations are the location of the static port and subsequent effect on indicated airspeed during the slip.
If you slip, it is usually to lose altitude. Therefore, getting the nose down is important. If not, you will lose airspeed rather than altitude.
In general, it’s a good idea to avoid slips since disorientation is possible. Therefore don’t slip in the clouds. Avoid slips with passengers on board due to disorientation and potential motion sickness.
Know your Pilot Operating Handbook and limitations regarding slips in your aircraft. Practice slips to perfect your technique”