Couples who are about to get married do tend to follow the traditions of the concept more or less to the letter. Very often, this means that on the eve of the wedding the happy couple will, separately, go for a night out with their friends, generally those friends of the same sex. For the groom-to-be this is a “stag” night, while for his prospective spouse it is called a “hen” night. As different creatures as stags and wildfowl may be, the nights that bear their names are broadly similar. Alcohol is taken, frequently a stripper is invited, and a hangover on the most important day of your life is almost inevitable.
The stag or hen night is trumpeted as the individual’s “last night of freedom”. This in itself is a description which is losing some of its relevance, as usually the couple involved will have been living together for some time. Just what level of freedom they have prior to and including this “last night” is an issue for their own consideration, but it is wise not to test the elasticity of the description too far. If you spent your last night as a technically single guy or girl with a stripper, the excuse of tradition would be unlikely to spare you a very angry revelation later on.
That said, there is nothing wrong with a stag or hen night per se. Things do become more serious after you have been married, and those who have not had a final night of independent fun prior to this often regret it. Just make sure you are in a fit state to show up at the ceremony the following day.