peace to you friend. The method I'm strongly leaning to (in big part because I need it to look accidental) is Shallow Water Blackout. I learned of it here. There's loads of discussion about it here. There's a pool here at my apartment complex which is where I would do it, but the operative term is "Shallow" so many use it to ctb in the bathtub. the other reason I'm considering it is because it seems like a it shouldn't be distressing or painful. I hope you find what you're looking for.