You mean push back more? It seems to turn into more of a line if I push it back any further.
But I'm not sure what you mean by pressure. This is our first litter.
When sexing rabbits, it was easiest for me to have them on all fours, like on a table in front of me and lift up the tail. Then when you see the vent, if you apply a little pressure (push your thumb down gently right in front of the opening), if it's a boy the tip of the penis will pop out. It's been a few years since I had rabbits, so I'm trying to remember the best I can and describe it the best I can! Sorry!