Noun. It is the event or activity that is a direct result of ones wife or significant other going to the spa, allowing a window of opportunity for them to get together with their friends and partake in manly activities such as Sports, Drinking, Gambling, Fishing or a combination of all four. Manspas display a synergistic effect when a group of wives or girlfriends go to the spa together freeing up the corresponding husbands and boyfriends to enjoy their freedom as a group, resulting in a debauchery that is greater than the sum of the individual parts.
"I just found out that my Girlfriend and your wife are going to the spa this weekend. I'll get a case of rum for the manspa, you bring the other case of rum."