Which end of my avocado seed goes up, when sprouting?

the thinner end of the seed

As I recall in the days of placing just about every avocado seed that came into the house; the best position was to place the seed in water with toothpicks stuck in its side to hold the seed in place over a glass of water with the point down like looking at the Ace of Spades -- spade point down. The part of the plant that emerges from the seed first is termed a radicle. The root radicle came out near the point but up on the side a ways. Doesn't make any difference how the seed is oriented for germination, two cotyledons, plumule, epicotyl, and the hypocotyl all emerge from the side - a bit closer to the point and then go their respective directions.

Always the pointy side up. I have done this many times. Be patient...it can take over a month before you see any roots or sprouts happening.

the top part the roud skinny piece goes on the bottom

I got one growing it is about time too

I been trying 4 ever

it is now ten leaf high it likes lots of water and light

I keep it under lights with my other plants and flowers

Regular tap water will work fine.

it doesn't matter

the sharper or thinner part.