What is the ruling on a wife asking for money during intercourse or cohabitation, even if it is in jest?

If a wife refuses her husband until he gives her money in exchange for intercourse, this is impermissible and a grave sin. The angels curse her until morning. However, if it is done playfully and as a jest, it is permissible as long as it does not harm the husband. It is better to choose kind words to foster affection.