This placard is said to hang on the wall of a rare bookstore (in both senses of that phrase) in London. I can see why a bookseller would display it, but the advice is more truly directed at the patrons of sex workers, and I think it good:

The quote is attributed to John Selden and appears to have been published in his posthumous and sometimes-questioned Table Talk.

Similar Sex Blogging:

• "We're Gonna Need A Bigger Bed"
• Fancy Brothel Date In Days Of Yore
• Ye Olde Basket Trick
• A Moment Of Sharing In A Brothel
• "Fuck You, Pay Me"
• It's OK To Pay For Sex