I play in a jazz band and we are playing some Latin pieces. In "One Note Samba" there is written "in stand". What does that mean? How to play that with the trombone?
you literally just point your bell into the stand, not directly touching it, but the sound should be muted by the stand
You put your bell about 6-8 inches from the stand, so it gives the trombone a muted effect.
If your worried about catching your bell on the stand, try a bucket mute for a similar effect. It may be about keeping control of volume, or it could be a stylistic effect.
I think the 'Stand' in the mind of the arranger is the dance band type, a substantial wooden structure used to front the band and bear a logo as well as merely support music. Pointing the instrument into this would have rather more effect than into the lightweight tripod stands we commonly use.