Flashed Once

Years ago a work boss who I had a strained relationship did the unexpected. We worked at a very stressful Health Insurance company in a call center. All the calls consisted of getting curse out from impatient people. In fact we had a high employee turnover rate too. The female boss was always short and in a hurry with me for years I worked with her. One day she called me to a conference room to do the dreaded performance review. We were the only ones in there. After some small talk she got out her seat walked over to me and pulled down her blouse to show her large breast. Her breast were impressive for an older lady. I am in shock, and just ignored her come on b/c we never got along, so I just acted like didnt happen and kept it moving. What would you do?