Overall, couples have to be really turned on to engage in anal sex. Receiving anal sex can be very painful if the muscles aren't adequately relaxed and getting super turned-on helps make it an enjoyable experience. 69 requires much less turn-on than anal sex, but requires more than all the other positions. Couples are in perfect agreement in that the missionary position requires the least amount of turn-on. In general, men don't have to be as turned on as women to get into any of these positions.
Anal sex requires a high level of passion, for both women and men.
Don't attempt this cold-it might not work. Overall, couples like to go deepest with doggy style, then woman on top, then man on top. They like a little less penetration with 69 and anal sex. However, it seems that none of the positions are conducive to very shallow penetration. On a scale of 1 to 10, the lowest position fell on the 6.