The same thing can be done from the opposite direction, for instance from G, top space in the staff to G one octave higher. Glissando from G to A (whole step) and then slur up to G octave. Once again eliminate the glissando but keep the feeling of blowing through the slur that the glissando produced. It is important to remember that that slide cannot be moved at the same speed over different distances to produce the same legato. Half steps should be smoothed out accordingly to match a shift of several positions and vice-versa. It is also helpful to practice bending partials in the same position because they tend to pop out faster and cannot be sustained in between notes as much as a legato slur unless practiced. Don’t be satisfied with what the horn gives you, make the horn give you what you brain decides you want. Virtually any type of slur is possible on the trombone, so why not go for a great one instead of what everyone else does. The same applies to sound and just about every other aspect of playing. The trombone is capable of the most beautiful legato in the instrument world, so let’s stop apologizing for that and guide our younger generation of players toward this realization, something the great composers understood long ago. Every time I play a legato passage I think to myself,  “Can I use less tongue?” Using less tongue in legato means putting more resonance into a particular dynamic and resonance is the name of the game.