There is no difference aerodynamically. The only difference is intention and presence of the wind. Airplane does not care about ground track, all it feels is movement through the air. Both side- and forwardslip makes airplane to fly slightly side-wise through the air, somewhere in the direction between nose and downwards pointing wing.

If there is no wind, your ground track will be exactly the same, between wing and nose, and you feel, that the nose points away from your track and call it forward-slip. If the wind is blowing and you manage right amount of the slip, you are moving side-wise through the air, but the ground track (combination of wind and slip- movement) can be aligned exactly with the nose and you call it side-slip.

There is really no difference aerodynamically and thus no difference in applied controls neither.