I have side-slipped a 172 on finals and it is no big deal really. Indeed, in the good old days, that was the only way to get a Tiger Moth down at all(so I'm told)
However, as you are deliberatly putting the aircraft out of balance the feeling is quite disconcerting and extremely uncomfortable. The trick it to anticipate things a little earlier. Remeber that you don't want the aircraft to take you somewhere your brain wasn't 5 minutes ago. So don't try and side slip down to 20 feet. Draw the line at maybee 150-200 feet. Give it time to stabilise before touchdown. This means entering the side slip earlier and coming out of it earlier. Be sure that you can make a good safe ordinary landing. If you are not comfotable that all is well by 300 - 200 feet then a go around is sensible. Remeber, no-one ever colided with the sky!!!