My first anal???? How to receive painlessly?

I've dreamt about anal sex & losing my anal virginity for years, and am desperate to feel a cock in my tight virgin hole.

But recently I FINALLY got an opportunity, be it in a seedy toilet, and could not relax to take the cock in me - I've used dildos of a similar size & girth, but the pain was unbearable.

Is this just the way it is on your first time, or is perhaps bent over in a cramped toilet not the easiest way to relax (I've answered my own question I think???!!). But how do you take your first cock??

I'm desperate to fulfil this experience, but nervous that my one failed attempt so far means I can't? How do I relax, what position is best for 1st-timers, and any advice???? PLEASE HELP!!!