sheath tuck
A detached_sheath* that is "hidden" (or presented, if viewing the character from behind) by pushing it between and behind tightly pressed thighs. This is sometimes drawn in ways that are anatomically impossible. *(generally non-detached sheaths can't do this or show obvious stretching, so include this tag if it looks otherwise impossible)
If there is any amount of erection, also tag penis_tuck.