Mr. Mayor,
Slips are nothing to worry about - a very useful technique, and they can also, in the right aircraft and under the right circumstances, but a whole load of fun!
1. You'll need to use both pretty much simultaneously, or you'll initiate a turn. But it's quite common to yaw the nose to, say, 10 degrees off your heading, and use the appropriate amount of aileron to maintain your track - doesn't really matter. Just dowhatever works best for you.
2. Definitely don't use a lower speed. Normally, the same speed will work fine. You can use a faster speed if you want, to lose a little more height, but depending on the type of aircraft you might find it difficult to get rid of the speed afterwards. Also, if you have flaps (and gear, in a more complex aircraft) down at the time, you'll need to watch out for not exceeding the flap/gear limiting speeds.
3. The main danger of spinning comes with a skid, which is when you use too much into-turn rudder during a turn. In an aircraft which is approved for slipping, there should be no real danger. Best advice, as always, is to watch your attitude and make sure you stay well clear of the stall.
4. This is very specific to type. I believe that some Cessnas don't like to be slipped with flaps, but others do - check your POH, and check with your instructor. Also, just because something's allowed, doesn't always mean it's a good idea. In my Europa, it's quite tricky to maintain speed control while slipping - so I've set myself a personal limit not to slip with flaps until I've got more experience on type, because of the danger of inadvertently exceeding the flap limiting speed - once I know I can control the speed more accurately, I'll remove the self-imposed limit
5. Absolutely!
Also, I usually prefer to slip with the left wing down - this gives a better view of the runway.
The best advice is to talk to your instructor. He will know the type of aircraft you fly, and he'll also be able to demonstrate things to you, which will always be better than us lot trying to describe things with words.
Have fun!
FFF
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