do a Google search on auto fellatio, and you will get lots of responses including:

http://www.chicoachico.com/auto-fellatio/

I must say that when I was 14-15 and doing yoga (my first sexual experience was with my yoga teacher!), I tried this.

I was able to get it in my mouth a few times, and came on my face. I haven't thought about it much since then, and I am not as limber at 46.