Anyway, to get back on topic of what OP was asking. I have the canine 2 hole from
here and I have found that if you use it without the plugs at the end you can usually go longer without cumming. alternatively you could try forcing air into it so that the internals are expanded rather than creating a vacuum where the internals squeeze and around you. If you have a toy with multiple orifices; you can set one up for tight intense pleasure and another one for lighter softer pleasure and just switch between the two depending on your arousal level and how close you are to the point of no return. Lastly, you can always put yourself in a position that makes it hard for pressure to be applied to your prostate you can usually go longer. For instance, if I want to cum fast (under 3 minutes) I will squeeze my legs tight together or sometime cross them and stretch them out as hard as i can while holding my hips in a slight forward-thrust position and if I want to take my time (45m - 2hrs) and really build up my orgasm I will get in the doggy style position and kinda squat back on my haunches a little like I was getting ready to sit on a dick and hold that general position while I thrust and stroke my toy slowly!
I usually like to cum fast so I can get back to the tasks I need to do that day but sometimes when I have a lot of free time I really enjoy just taking my time and building up big, sloppy. body-convulsing orgasm.
Hope this helps! cheers!