Rapid Comfort is a trombone slide lubricant from the makers of the venerable Slide-O-Mix 2-bottle formula. With Rapid Comfort, you have a simpler application with a single bottle. The silicone and soap combination is pre-mixed, so a single bottle will do it.
To apply, wipe off the inside slide tubes, swab out the outside tubes, and then apply about a 4" line of Rapid Comfort to each inside tube. Work the slide tubes together to distribute the lubricant. If it's gummy, add a spray of distilled water. If not, use as is.
Rapid Comfort and similar liquid slide lubricants work best in newer slides in good operating condition. If your trombone slide has some miles on it and makes noise from motion, or drags here and there, consider a cream lubricant like Superslick or Trombotine. You may get a bit smoother and quieter action from those. Then the uber-trick is to add Rapid Comfort on top of that.