Using Slide Cream
Slide lubricants are perhaps the most over-discussed topic in trombone playing. I use Trombotine (slide cream) on my slide, but there are a plethora of other lubricants on the market. It's a very personal subject amongst players and teachers, so let's just rest with knowing that this is what I do and it works for me. Your mileage may vary.
No matter what the lubricant, the first step is to wipe the inner slide clean (use a cloth or tissue) and then clean the outer slide with the cleaning rod. Then apply lubricant to the inner slide, and finish by spreading on the outer slide.
Trombotine comes in a tube and it feels and looks like face cream. According to ancient trombone myth, Trombotine and similar creams are based upon the formula for mid-20th-century Ponds Cold Cream. Whatever the case, a little dab is enough for the whole slide.
I place two spots of cream on each slide tube. One spot is the stockings (the place where the slide changes size, near the bottom). The other is about 1/3 of the way down the slide, near 3rd position.
Spread the cream around on the slide using your hand (non-poisonous to the touch, but don't eat it!), but avoid over-spreading. Try to achieve a consistent, thin layer. The final coating is just about invisible. Thick, white streaks are a sign of poor coverage, and will probably lead to a sticky-feeling slide.
Coat the outer slide one tube at a time, using the inner slide. A few fine mists of water provides the perfect lubricant on top - liquid ball bearings.