Leviticus 15:20-24

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.

Whether it be on the bed or on the thing on which she is sitting, when he touches it, he shall be unclean until evening.

If a man actually sleeps with her so that her menstrual impurity is on him, he shall be unclean seven days, and every bed on which he lies shall be unclean.