Definately had the same problem BUT, While I had someone holding the female, I got him proped up on a phone book/blanket or whatever was closest then I reached underneath the female...(not for faint of heart)...then I lined him up using my finger and while in motion to took my thumb and made sure it found it's home and stayed there...trying to be pg13 about this. Sometimes I miss and thats that for right then. My dog would get distracted only if I physically moved him, as long as he got the right end we were golden. It's a serious matter of patience. keep trying, he will eventually figure it out.
Tino ended not minding me helping him once he had his first tie with the female~ they definately get the idea
And speaking of~ Tino is now a daddy of 6 puppies! On his and the females first time!!!
