I bought today a snake tube of 85cm ... very long. I was eager to try it but I knew I had to be careful.
I tried it gently first, after several soft strikes I felt it could not go further (only 20cm deep).
So I was patient to persevere, to rest a bit and try a second time, pushing it gently forward and then ..... woaw, it went deeper, and deeper, and deeper. It was an incredible feeling. I am so happy I bought it.
I am impatient to try it again tomorrow.
Thanks a lot to all for your advices here :-)