Don't watch YouTube.
Recognize the difference between averaging down and scaling into a position.
Generally, averaging down means you're wrong and you keep increasing your position and risk in order to get out at even or for a small profit. It usually don't end well. The problem with this is that it can actually work very well at times, so you may start thinking it's a smart approach.
Scaling into a position where you have a plan in advance is different, i.e., I'm expecting a pullback to 15-10. You take your first entry at 15 and take another entry at 10. As long as your risk management is correct and you have a plan I don't see a problem with this.
Generally, I prefer to add to a winner, though, so I may choose to instead take the first loss and get in at a better price around my stop-out point or lower and then build a better position as the market proves me right (by moving in my predicted/anticipated direction). That's the way to bring home some really big winners without taking on much initial risk at all.
Best example is a smooth trend day where you have an early entry and keep adding while your average is still way below or above market.