Maybe Tyrone Slothrop's ancestors weren't so uptight after all. A San Francisco Chronicle review of The Genuine Article: A Historian Looks at Early America by Edmund S. Morgan notes that under the covers the Puritans were a randy lot:

.... most Puritans believed in a woman's right to "that pang of pleasure" associated with intercourse. The laws of New Haven -- one of the strictest and most conservative Puritan enclaves -- allowed wives to summarily divorce impotent or underperforming husbands on that score alone....Puritan households exercised great permissiveness when it came to premarital sex. During the late colonial period it was not unknown for pious fathers to encourage "the young men courting their daughters to spend the whole night at it under their own roofs. After the old folks retired the couple slept together unattended....