The quote from P.G. Wodehouse's "Doctor Sally" humorously suggests that men who are less intelligent, referred to as "chumps," make better husbands. The advice to "tap his head" implies that a solid, dull mind is preferable when choosing a partner. The notion is that intellect can complicate relationships and lead to unhappiness.
This satirical perspective highlights the author's belief that having a simple-minded partner can lead to a more content marriage....