A skirt is no obstacle to extemporaneous sex, but it is physically impossible to make love to a girl while she is wearing trousers.
Source: In 2,715 One-Line Quotations for Speakers, Writers & Raconteurs, by Edward F. Murphy, 1981.
-- Helen Lawrenson, (Oct 1 1904-1982), US editor; She knew everyone, gossiped mercilessly wrote about it in Stranger At The Party: A Memoir, 1975.