Any good methods to CTB?

[fuyufuyu]

I need a good secretive way to ctb. I don't get much time when I am truly alone for some time because I still live with my parents. They don't like it when i try to CTB but don't like send me to therapy or somthing. I tried OD but all of the 3 times I tried, it never worked. Now i feel disgusted and repulsed by any type of meds. I tried suffocating myself with tightening a skipping rope around my neck but i gave up since it was taking a lot of strength out of me. My first 2 times were dumb methods. Any good reliable ways to CTB without like buying suspicious stuff to outsiders? My parents also are monitoring my spending so i can't get away with like any substance. I've been thinking of getting some good tape to shut my mouth with and stabbing myself but i don't know.. Please help with a good method!