As the range of supports available increases, so does the range of positions that are possible. Also, various forms of erotic furniture and other apparatus such as fisting slings and trapezes have been used to facilitate even more exotic sexual positions.
Pregnancy is a potential result of any form of sexual activity where sperm comes in contact with the vagina; this is typically during vaginal sex, but pregnancy can result from anal sex, digital sex (fingering), oral sex, or by another body part, if sperm is transferred from one area to the vagina between a fertile female and a fertile male.
For example, the spoons position is recommended when either partner has back problems; the starfish position is recommended to achieve orgasms more easily and the missionary position may be uncomfortable for the receiving partner if the weight of the inserting partner, relative to the receiving partner's, is a problem.
Other physical limitations of one or both participants also limit the sex positions which they may adopt.It may also be performed simultaneously (for example, when one partner performs cunnilingus, while the other partner performs fellatio), or only one partner may perform upon the other; this creates a multitude of variations.Simultaneous oral sex between two people is called 69. They can lie side-by-side, lie one on top of the other, or stand with one partner holding the other upside down.Sex manuals usually present a guide to sex positions. In the Graeco-Roman era, a sex manual was written by Philaenis of Samos, possibly a hetaira (courtesan) of the Hellenistic period (3rd–1st century BC).The Kama Sutra of Vatsyayana, believed to have been written in the 1st to 6th centuries, has a notorious reputation as a sex manual.Scenes of multiple penetration are common in pornography.