I would think man on bottom.
you might choke her.

how about man take head out of ass first

but I would think woman on top, man on the bottom.
That way the woman has greater range of motion for moving her head up and down, and also can grind a bit with her nether regions.

It seems that the man would have less need to be able to raise or lower his head as much so it against a surface wouldn't be an impediment, and also if she is doing the moving with her head he would need less range of movement with his hips...

So, based soley on my own ignorant logic, woman on top, man on the bottom.

Just 69 ! LOL

mmmmmmmmmmm

But whoevers on top.. Just make sure they wash their ass

-- Modified on 2/27/2006 4:54:09 PM

Either partner can be on top, but peforming is significantly more difficult when in the bottom position, due to lessened mobility and the effects of gravity on raising ones head.

There are other variations of the 69 position, however.  The side-by-side position is popular, as it gives equal access to both partners, without either having to support the weight of the other.

Another interesting variation is the standing 69 position (pictured below).

Yet another involves the woman lying on her back with her head hanging over the bed, and the man standing at the edge and slightly bending over the bed.  The woman then lifts her torso towards the man, locking her legs around the man's waist while supported by the man's hands behind her buttocks.  This variation is similar to the standing 69, except that the bed is used to help support the woman.  Pillows or 'the wedge' can be placed behind her back to provide additional back support.

Here are several links with descriptions of sexual positions, including the 69 position:

http://en.wikipedia.org/wiki/List_of_sex_positions
http://www.askmen.com/love/love_tip/50_love_tip.html
http://www.sexinfo101.com/

- The Advisor

...whatever works best for you, and her, at the time!!!