personally speaking this is how it works for me. Cialis I take it and usually crush it and swallow the crushed tab with water. about 2 hrs or there abouts I can actually feel it starting to work, usually followed shortly by an erection. it'll subside in time and over the following 24 hrs I usually get erections over just about everything: pants brushing it a bit, strong gust of wind, thinking about anything even remotely sexual, or sometimes just outta no where. they usually subside if no further stimulation happens, and I usually wake up with a raggin wood. heck first time I took it I woke up 3 times in the middle of the night because my erection got that hard, and I usually sleep like a rock, but then again I did take it just before bed too. anyways over the next couple days or so (usually lasts 3-3 1/2 days for me) it calms down some and usually only rises with stimulated, but I still will get the occassional, outta no where wood. Personally I got it for girth work as well. I did find during that time I can go a great girth workout and it will still rise again with no prob for whatever may come later. but I defeinatly would not recommend taking this and trying to hang. I just couldn't bring myself to do it, besides to much of a chance to damage something. but for Penis Enlargement work it is great.
IMHO the 36 hr thing must be only for those who do have ED to some exstent and those healthy get effects much longer than mentioned. makes me feel like I just hit puberty again..lol