Leviticus 15:23

And whether it be while she is on her bed, or on a seat which she may happen to sit upon when he touches her, he shall be unclean till evening.

And if it be on her bed, or on any thing whereon she sitteth, when he toucheth it, he shall be unclean until the even.

If it is on the bed, or on anything she sits on, when he touches it, he shall be unclean until the evening.