As I said above, when you are learning a technique you need to spend time mastering it and the only way to effectively do this is to do 1000's of reps under the guidance of your instructors.
I'd be concerned at why you are "chicken to ask for more help from your sensei". If you don't get along with him/her then maybe you should be asking yourself if it is time to move to another dojo where you are comfortable to ask for help.
The teacher is there to help and teach, the student is there to learn. If you aren't learning and the teacher isn't teaching then find somewhere that does and get out of there.
I would be quite upset if my students felt they couldn't ask me for help. They ask all the time and I try to help them as constructively as possible, that's what its all about! Every MA student starts at the beginning with 3 left feet and 2 lots of un-co-ordinated hands.
Remember that and go and practice some more! Otherwise I will set you a couple hundred pressups and situps a day until you do pull finger and practice.