Leviticus 15:18-22

If a man sleeps with a woman so that there is a seminal emission, they shall both bathe in water and be unclean until evening.

‘When a woman has a discharge, if her discharge in her body is blood, she shall continue in her menstrual impurity for seven days; and whoever touches her shall be unclean until evening.

Everything also on which she lies during her menstrual impurity shall be unclean, and everything on which she sits shall be unclean.

Anyone who touches her bed shall wash his clothes and bathe in water and be unclean until evening.

Whoever touches any object on which she sits shall wash his clothes and bathe in water and be unclean until evening.