Dum question about $ transmission

I’m afraid by myself. Here is my problem :

I have an icon on my post page (single.php) whitch open a popup. I want inside the url of the post… but I use permalinks and I don’t know how to transmit this $.

I say this $ because I want the same icon on each post of my blog… Do I need to write some complex lines in htaccess to make only that ? Or am I a pure idiot because the solution is simple as clear water ?

I prefer to be an idiot. Please, prove me I am ! ??