Well I've been playing for about three years now and I recently found out that when I have to play tremolo stuff finger style I don't just hit the string downwards with my fingers, but I also the string upwards with my first finger so it goes:
I can play pretty fast with this in a clean sound, and it does stress my hand or anything so haven't really though about it until now.. I would record a video or an audio example, but I don't have any gear for it. Do you understand what I'm talking about and is it wrong/bad in any way?
There are no wrong ways to play a bass...however, there are recommended ways.

If what you're doing now works, and it's not hurting your hand, and it sounds OK, then keep going with it. But you can never go wrong with a 2-1-2-1 style of playing.
I understand,

I do the same thing! Hasen't hurt my hand, although I just found out I do that naturaly.
Plus, Double the speed without the extra effort.
I think I see what your saying and its a sort of trick I used in a musical this year.

One song we played every once in a while there would a short pause then the piano player would take her hand and with her thumb and pinky play octaves back and forth really really fast, essentially a tremelo type thing. My part called for a tremelo on a root note at the same time and I could never keep up with her. Instead of grabbin a picl for one note then putting it down and pickin it back up and so forth I used your technique.

It was sorta like using the middle finder as a pick...but I don't see anything wrong with it.
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