Perseverance finally paid off... I have manged to fist myself! Exhilarating to say the least.
I thought I'd never achieve such a feat even if I was fairly close to doing it; a few weeks ago I decided to give it up as, no matter the effort, it just wasn't happening. I ready many 'how-to' posts on various forums, tried a number of suggestions (like sitting on my hand to force it in...) but couldn't get it right: so close but yet so far. I accepted the idea that self-fisting was reserved for just a few anatomically gifted ones.
Anyway, a few days ago, I was rinsing my ass to prepare for some anal fun and, incidentally, I used some particularly foamy soap that made my fingers slide in and out my butt-hole much more effortlessly than usual; so I thought I'd use the soap as a lubricant rather than the regular Vaseline. Indeed, I found that I could insert quite smoothly even my (homemade) objects/toys just by using the soapy foam as lubricant. This somewhat instigated me to attempt inserting some larger toys which, to my surprise, I managed to do with little endeavor.
So, to cut a long story short, this paved the way for a few attempts at self-fisting. My ass was nice and loose but the soap just wasn't doing the trick so I got hold of a generous amount of Vaseline and the next minute my fist is fully inside may anal cavity. What an insane sensation! My ass feeling crammed while, with my hand, I could feel the walls of my rectum at the same time. It is true what they say: it is totally mind blowing!