The 8th function is something that you are quite confident in but you don't take seriously, that is, you don't see it as a priority in your life and you think that those who do see it as a priority are misguided.
Therefore, the 8th function is connected to things you do in your free time for fun but that you don't really want to make a career of it, or spend too much time on it, and you think that those who do are "over the top". Also, unlike your quadra functions, even the base function, where you will resent criticism because you value them, you don't really care about what people say about your 8th function, because it's not important.
Since your 8th function is strong but it's your dual's PoLR, it can't be something you expect from your partner, or that you'd want your partner to spend much time doing, focusing on, or being good on.
So -- if you can think of something that you enjoy a lot as a hobby, but yiou wouldn't want to spend your life doing, and you don't expect others to like it (and would even be repelled by someone taking it too seriously), then, that something is likely connected to your 8th function.