1,067. Distancing
153:4 Leviticus 18:19 says, "Do not approach a woman in her state of menstrual uncleanliness." From the words "do not approach," we understand that any kind of approaching is not allowed, such as joking around and levity. One may, however, be alone with one's wife when she is a niddah. Since they have already had marital relations and will be permitted to do so again once she has immersed in a mikvah, we assume that they will be able to control themselves and not have relations while they are prohibited.
153:5 When a woman is a niddah, her husband may not even touch her little finger, nor may they pass anything from hand to hand. This is the case even with something that is long, where their hands won't accidentally touch. Even throwing from one to the other is prohibited.