If I'm understanding you, say the wind is coming from behind, pushing the plane away from you, you are using the rudder to point the nose of the plane towards you. If that is correct then side slipping would kind of be the opposite since you would be using an opposite rudder input.
The 4*120 would be a great plane to practice the side slip on. I used my 4*60 for it. I learned by picking a day with the crosswind coming from my back. Got the plane very high lined up for a landing. Cut the throttle, then tilt the wing so the close wing is low, like 30 degrees and gave full low rate rudder to turn the plane away from you (kind of like doing a knife edge). Leaving full rudder, use the ailerons to keep the wings angled and the elevator to keep it lined up with the runway. The plane should drop like a rock compared to floating it in. The rudder is creating a huge amount of drag and keeping the plane in line with the runway instead of crabbing. Eventually you can fly it down to just a couple feet off the runway before leveling the wings.
Here's a vid of a full scale. The way he's doing it would be exactly as described with the wind coming from the right side of the plane. Dip the wing on the side the wind is coming from, in this case the right, kick hard opposite rudder, in this case left. Then use elevator to line up the runway.
Side slipping a warbird though is tough. I would not do it nearly as much, just a slight side slip to help keep it lined up, not a severe one to create lots of drag.
https://www.youtube.com/watch?v=evgsfgpT-7w