If you don't see it printed, it sounds like a session for men. In my opinion a portmanteau is only a good portmanteau if its meaning is unambiguous in both spoken and written forms. This one clearly fails the uselessness test. ;-)
How do I know that this doesn't refer to men seceding from something, or to a procession of men, or to men ceasing to exist (a "man-cessation"), or if I simply hear it, to a session of some body at which women are excluded. This tendency to form portmanteau words at the drop of a hat (at a drat!?) really gets my billygoat gruff. No problem, if it's done in jest, but when people start acting like these are serious words, I start getting a little scared.