You could try something involving vibrators on a low setting taped to you in various places and not allowing yourself to cum until released or a certain time is passed. Done that a few times myself but not managed not to come yet...

One suggestion I read about on a forum involves using coded padlocks, a dark room and a lamp set on a timer to go on after a certain time. You turn off the light so that it is completely dark, lock the cuffs with the padlocks, randomise the numbers and then wait. The idea is that you cannot escape the locks until the light comes on so that you can see the numbers on the padlock. There is a risk with this (and any method involving electrics or electronics) that the timer will fail (power cut, bulb blowing etc) but you can minimise this by having alternative escape plans - for example making it so you can wriggle out of the door into a room with light or have an emergency source of light nearby.

You can also arrange with someone for a time when they can assist you online with the bondage. For example, they can send you the padlocks set to a code you do not know. You tie yourself and then wait until they send you the code.

One idea I read about involved tying yourself in a position where the shower is aimed directly at your private parts thereby giving you stimulation while you are tied.

You can do a limited degree of self mummification using cling film - similar to the bin bag one you mention above.

There is apparently a way to do a self hogtie but I have never figured out the directions properly and it does require a knife to escape the bonds. Not been confident enough to try this at all.