For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
As long as it does no harm to the Lord's holy temple (our bodies) and it is used in the relationship of the marriage bond.. I see no issues that would contradict biblical teaching. The mans body is for the wife's pleasure and so it is with the wife's body for the man's pleasure. As long as it is consenual between them in the marriage bed that is undefiled. It would be like taking an asprin, or any other prescribed medication. It isn't how, but with who and what's in your heart that matters to God.