Hot tub

From Voyeurweb's Wiki

A Hot tub is a tub of hot water, generally large enough to accommodate multiple people at once. A hot tub does not feature jets, bubbles or other types of water agitation. Hot tubs were very popular in the 1970's, prior to the introduction of jacuzzis and spas. As far as rumors go, hot tubs are more often used for masturbation than for sex with others.