In the tool I use for keeping my context lists and projects, Omnifocus, I just put it next after the real next action, set the project to sequential and leave it. Then as soon as I am done with the first one the second becomes available with no more intervention from me. I go ahead and give it the appropriate context right then. No sense wasting any valuable thinking time by re-doing something you've already thought out.
More generally that is what is called Project Support in the GTD system. YOu can just put it with other project support materials.
Oogie McGuire - Mac, iPhone & Omnifocus
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Paonia, CO USA