Uncut here.
My technique is to use a medium butt plug and exercise my hole for about 3-5 minutes with the widest part of the plug. Lube up both my hole and cock with silicone lube very generously so it is nice and slippery.
Now the position I use is the standing up cowboy position with my legs ahead of me. I have used a toilet seat lined with a thick towel cushion for my hand and more recently, a computer tower with a pillow. You could use something similar.
The insertion method I use is similar to this:
http://www.xtube.com/watch.php?v_user_i ... view_flag= with my dick inverting to the left, and then behind me along my crack.
I make sure there is as much as my shaft behind me as possible, then use my right hand to push below my head (with my index, middle, and ring fingers) torwards my hole. And at the same time, use my left hand to reach behind me (not through my legs) and push my cockhead again torwards my hole. Use the computer tower or what-not as leverage and as an object for balance.
Take a deep breath, relax yourself, especially down there. This is where the pillow comes in handy, you have to sit on your right hand while pushing your cockhead in, essentially also fingering yourself. Use an 'up and down' motion, slowly fucking yourself, working your way in till your cockhead pops in. The first few tries it will partially go in, but keep at it, re-lubing when needed. I don't even have to worry about my foreskin, it will go in when my head goes in (your story might be different though).
Once your head pops in, tighten your hole a little bit and try to flare your cockhead with blood. Usually works for me so I can get ready for the next step. Take your left hand and push down on the base of your dick along the shaft, to further push your dick behind you, ending with your fingers pushing your head in. Repeat the same with your right hand again.
I hope this helps in any way possible. If I get tight and start having trouble again, I use the buttplug again for a little bit (doesn't have to be too long, just to open yourself up again).
I am doing the same as this guy on solosuck.com :
viewtopic.php?f=3&t=4265