http://www.get-back-on-track.com/en/professionals/00_meta/09_produkte/p_con_0009_01_03.php
http://www.extremefitness.com/forum/showthread.php?t=444
I've read a good bit on this stuff, but never done it. I think caution is advisable. The Nebido and Sustanon products are not available in the US. Sustanon is apparently available in CR, Nebido may be either now or in the future.
With respect to Nebido, this is just way too much, don't do it. It is designed to be injected like once every 3 months, and that's messing with your body way too much to simply be more virile for a week or two.
One dose of Sustanon 250 is probably about right for a two week or 10 day trip, although from reading the internet it appears that by 14 days testosterone levels will have returned to baseline, so one might argue that a booster would be in order after a week or 10 days.
All this stuff is kind of crazy, because you are messing with your body, but probably if you only do it once a year or so, a single dose of Sustanon 250 would be OK. As far as the time it takes to kick in, it is supposed to be fast-acting, either same day or next day at the latest.
Obviously I ain't no doctor, and there is certainly some risk in doing something like this.
These products are not available in the US, perhaps for good reason.