Mirror play incorporates mirrors into sexual or BDSM activity - allowing observation of the body or acts from different perspectives, creating doubled visual effects, or adding psychological elements.
Mirrors can be used to force observation (particularly in humiliation or submission contexts), to create visual interest, or to allow the submissive to see what's being done to them.
The psychological element varies - some find mirrors grounding and present, others find them voyeuristic, and others find observation of themselves psychological submissive.
Safety is generally low-risk - ensure mirrors are secure and won't break, be aware of reflective glare, and respect boundaries about observation.