More practice. Don't get obsessive about it, and don't let it interfere with your fun times ... but maybe one dive a day, practice making a direct ascent. Keep doing it until it feels like it ain't a big deal (because it ain't, really). Once you're comfortable with making direct ascents, then try one while sharing air.
Rinse and repeat ...
... Bob (Grateful Diver)
UPDATE in case anyone is still aware of the original problem
. (We are back at home now).
The last 6 dives or so, we did straight up ascents, no line, with a safety stop. We weren't perfect, but it was comfortable and, I guess you would say, easy. First we did them from 25 feet, then from 40 feet. Emily was nervous doing it from 40 feet (which, to my mind, is exactly the reason we need to do them). On the last few we shared air, and had some trouble maintaining correct depth.
We were very successful doing them in a vertical position, when we tried horizontal, we had much more trouble holding the correct depth.
If the original situation should happen again, I would say we're quite prepared to thumb the dive and ascend with little added anxiety. We haven't done any of this in currents, though.
Emily still says she wants to take Fundies! We want to get more comfortable in our drysuits first.
Thanks for all of your help!
- Bill