Quit planning every move out step by step! That truly takes the FUN out of the experience. Get out of your head and just go with the flow. Most of us ladies know how to get the job done, several times.
Just tell the lady about the issue beforehand, then during the proceedings ask her to slow down, as necessary. Sometimes with me her sucking or jacking gets so slo-mo it's almost like a freeze-frame, but her willingness and ability to comply with that simple request is actually a great measure of her worth as a provider.
Usually I just try to slow down or I ask them if I need to paced slower.
Sometimes a new adventure can make you pop quick, just pump the breaks and try another activity, make the best of your time.