69 is a sexual position where both sex partners give oral sex to the other simulaneously.
69 is a common sex position where 2 sex partners lick or suck each others' genitals. They must face in opposite directions and curve their bodies to do this, which gives their bodies the look of a 6 and a 9. 69, or sixty nine, can be done as foreplay or can be caused to bring one or both participants to orgasm.
Since many men and women find giving and receiving oral sex to be pleasurable, the 69 position allows both partners to enjoy receiving at giving oral sex at the same time. A finger or sex toy can be inserted into either or both parters' anuses or vaginas for futher sexual stimulation. It is not uncommon to see people in gay or straight porn 69 before intercourse.