For modern flying, into fully equipped airports with ILS approaches, you should never be in a position where you need to lose a lot of height very quickly.
As long as you have the GS and LOC within limits, and have a recommended approach speeds, sideslipping is unnecessary.
If you are in a position where you require a sideslip in order to lose energy, then something has already gone wrong and I would suggest a go-around and repositioning to land would be the safe option rather than flying untested manouvers.
If there's any doubt, there's no doubt!