I really like this topic, but have to admit that I never do self-bondage that is potentially dangerous. I know, wimpy! BUT... The kind I do can take forever to escape. And I did have a particular glitch once:
I used white cotton clothesline, the very soft kind. I tied each ankle with about six feet of cord and, facing my bed, knelt at the edge (facing the head board) and working the line under the mattress on each side. Then I knee-walked a bit and then lay on my belly. I reached for the head board and gave myself a good yank with my legs, and voila! -- my legs were spread wide apart at each of the bottom bed corners. The only way I could get my legs loose would be to wriggle back towards that end of the bed, and push my feet away from the mattress.
But after getting my legs splayed apart, I bound my each of wrists with about a yard of cord each. I wrapped each wrist many times, and then stretched to push my hands and wrists through the upright poles of the headboard (there were, I think, 7), with one wrist either side of the center pole. Then I took the remaining lengths of rope dangling from each wrist and wrapped it snug against a pole, and finally knotting it on the outside of the bed boards. It took dextrous fingers later to get that knot undone, but that's what made the bondage work so well. Everything needed for release was dependent upon my reaching and untying a trick knot just barely within reach on the far side of a stout bed pole.
I had been very horny because we had visitors from abroad, including the drop-dead gorgeous daughter, and all I could think about was doing her. When I got home that afternoon I thought everyone had gone for an overnighter to the beach, as they had planned the day before. Well, one of them stayed home -- was a bit jet-laggy. Guess who.
In my haste to self-bind I had neglected to position my penis correctly. I was naked, of course, and on my belly, and in my self-bondage sessions I'd just rub my cock back and forth over the smooth, soft sheets and cum. In my hurry, however, I'd failed to position my not-yet hard penis to face towards the head board under me. To my embarrassment and utter frustration, it was pointed towards my feet. And, now that I was bound, it was stiffening. I rubbed, twisted, jerked, and otherwise thrashed, but could not get repositioned or satisfied. I was going nuts and, after several minutes, decided to just untie myself and take a shower.
That's when I hit the problem. In jerking about, my struggles had caused to to keep yanking at the ropes, tightening the knot, and try as I did, I wasn't getting it undone. I knew it was just a matter of patience, but it's hard to be patient when I'm that horny AND frustrated in more than one way. However, all my thrashing had been a bit noisy -- remember, I thought I was alone -- and drew the attention of... guess who!
Well she took it all in very quickly, giggled, said all the right things to make me mortified AND feel like a slut. She called my stiff prick "Mr. Wiiggly," and decided he'd needed some attention. She got on the bed, sat between my legs, grabbed "Mr. Wiggly," and started stroking me. She'd read about sex, and talked about it with friends, but she was a 19-year old virgin, so when I started to cum she was thrilled. What she didn't know was how sensitive my cock gets during orgasm, but despite my pleading, begging, moaning, whatever, she kept on. "I want to see it squish out again!" she kept saying.
She got her wish, mainly because I was 23 and still in sexual prime, but it was ecstasy interspersed with agony for five more orgasms. She finally quit and helped release me only when a very spent "Mr. Wiggly" went limp and small again.
Granted, I was lucky, but if ya gotta get stuck in self-bondage, that's the way to go. And yes, we fooled around for the next three weeks of her visit, until the family flew home.