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A quick bath or shower where one washes one's self except for the hair. It is usually very quick, up to about 5 minutes.

Also, not necessarily done before or after sex. A primary reason for a spit bath might be because your hair isn't dirty yet, so there's no point in washing it. May also be used to simply freshen up.
After a long day at work, Susan wanted a spit bath before heading out with the girls.
by Cravin' some raisins October 21, 2009