This one comes from Recovering Biblical Manhood and Womanhood where Piper is trying to deal with the fact that women often find themselves in positions of authority over men. Apparently he thinks masculinity and femininity hangs in the balance in the mundane exercise of a woman giving driving directions to a man:
To illustrate: it is simply impossible that from time to time a woman not be put in a position of influencing or guiding men. For example, a housewife in her backyard may be asked by a man how to get to the freeway. At that point she is giving a kind of leadership. She has superior knowledge that the man needs and he submits himself to her guidance. But we all know that there is a way for that housewife to direct the man that neither of them feels their mature femininity or masculinity compromised. It is not a contradiction to speak of certain kinds of influence coming from women to men in ways that affirm the responsibility of men to provide a pattern of strength and initiative.