Place the "hud giver" script and "reposition hud" object into any modifiable chair. The hud will automatically ask for attach permissions when sitting on the chair, or when the chair is clicked by someone already seated on it.
Hud buttons:
[-]: closes and opens the hud
Chair/Avatar button: Changes the rotation of the buttons to match the rotation of the chair or your avatar respectively.
Position cube: Click and drag to adjust your position.
Rotation sphere and ring: Click and drag to adjust your rotation.
Both the position cube and rotation sphere rotate along with your camera. The distance moved and angle of rotation are affected by the distance from your camera to the chair. Zoom out to make bigger changes, zoom in for more precise positioning.
Does not save positions or animations. Should not interfere with other pose or animation scripts. Works for multiple avatars, but untested for more than 3 (if it breaks please tell me! SchitzoTiger Firehawk)
Animated GIF: https://i.imgur.com/kYVKvqK.gifv