http://youtu.be/3NYyRLGUMCY?t=1m40s
If I don't have a dedicated tool, I use the spine of the knife, be it fixed or folder, like shown in the linked video - lever blade-spine beneath cap and over the top of your hand. you can leave the folder closed.
Another one:
[video=youtube;aRx_kmvoosQ]https://www.youtube.com/watch?v=aRx_kmvoosQ[/video]
Warning, do not try when under the influence of stupid.
......I tried the knife technique and my hand rebounded. Bit my second knuckle of my left thumb pretty good.
It wasn't my first try either, I was just way too many bottles in and, well, you know. Happens.
Gave me a bit of a scare though. When I went upstairs to wash it out I saw some white bit hanging out of the wound like a baby tooth and halfway through removing said object, with the same knife, I started to feel faint. The dizziness came quick and strong; I was clutching for a seat within 30 seconds. Breathing was labored, sweat beading all over, no nausea though. Eventually I laid down on the cool floor and realized that my body was broiling like an oven. Once I shed the layers and cooled off enough to walk again I slumped downstairs in shame to look for a bandaid in a frat house.
My hopes were low. At this point the bleeding wasn't too bad and there never was much pain; just shame and confusion over literally "going faint" over a cut. Luckily no one was in the bathroom with me. Incidentally one guy did have a bandaid

I gave him so much beer that night.
Now, this never happened to me before. I would rate this cut as the second worse injury to date, the first would be skateboarding 20mph headlong into a steel pole. That one had blood, stiches, swelling, and overall pain.... right over my left eyebrow.
The symptoms felt eerily similar to heat exhaustion; basically every single symptom was there except nausea. The fact that cooling down my body helped immensely also helps me make sense of what happened. The most likely diagnosis is I had a Nervous reaction, fight or flight mode kicked in. Loads of adrenaline, and a splash of alcohol, was coursing through my bloodstream, raising my core temperature to dangerous levels in minutes and caused me to lose all composure.:foot:
In hindsight, I should have got stitches last night. But I went this morning and they cleaned me up, put some butterfly stiches, and gave me a splint and some antibiotics. The nurse wasn't too worried as my motor functions are fine. That white bit that hung out of the cut could have been either fat tissue or Collateral ligament tissue. Either will heal over time. " The collateral ligament of interphalangeal articulations of hand is the joint that breaks most easily out of all of the body's joints."
One last thing, I noticed immediately when the nurse said "must have been a sharp knife, it got you good."
I was smiling at that point, yep something's wrong with me.

So I asked him how much worse it would have been with a dull knife and he said, "oh much worse, it would've extended your recovery by days to weeks. Usually dull knives cut ragged, yours is perfectly straight."
I laughed, maybe to give myself one teeny bit to justify my, completely idiotic injury that could have severed joint tissue and nerves, giving me lifelong issues.

<-- Lucky Bastard
Main lesson? USE A WIDE BLADE KNIFE and if possible, use a closed folder.
Also if you don't look look as sharp as this guy
...be careful.