Tight enough that it doesn't slip off when you "pump" (lol) but not so tight that it feels like it is constricting the blood supply. Just get yourself a pack of extra larges and see if it makes a difference. If you don't want to risk wasting your money, surf the web and see if you can find recommended sizes for each type of condom that is out there. There is bound to be a site out there like that somewhere. Good luck and think happy thoughts. lol
"We can live like Jack and Sally if we want.
Where you can always find me
And we'll have Halloween on Christmas
And in the night we'll wish this never ends
We'll wish this never ends..."