New to this [I I'm A Sissy That Loves Strap On Sex]

Soooo my biggest fantasy has always been to use a strap on with a guy. So far I have only been able to get around the rim and the tip of my finger in. What’s a good way to find guys that would be into this? Should I just try to find bi guys? Also any recommendations on how to start like what’s a good starter size?