This kind of hurts is value, and as such, I propose a fix:
The persistent pose.
The persistent pose is just like a period pose (using a different character, such as ' or ,), but instead of being blurted once when triggered, its use sets a @persistent_pose message on the user, which overrides @look_place and any sit messages.
When the character stands up, sits down or starts walking (or other similar actions), the @persistent_pose message is automatically and silently cleared, or even not so silently: If the character unposes by moving instead of adding a new persistent pose, it's a simple matter of replacing "%N %…" with "%N no longer %…", possibly configurably.
All of this frees @look_place up to describe general demeanour, and adds a new avenue for failure-safe posing.
