Self deprecation, especially in humor, is a divisive topic. Some guys will tell you never to do it because it lowers your value. I disagree. Sometimes, self deprecation can come across as seeking validation. Like when a girl posts a selfie with the caption "I'm so ugly" she's clearly fishing for compliments. This is extremely low value, and doing anything like this will absolutely torpedo your interaction. Or, if you make several self-deprecating jokes in a row, it will start to come off like you're actually quite insecure and hide behind humor as a shield.

But when done correctly, self deprecation can be extremely high value. Specifically, self deprecating humor can be a very important tool to demonstrate modesty. This is a very important topic because often when guys are trying to demonstrate value they come across as conceited. If you're trying to build value by talking about accomplishments, successes, talents, etc then adding in a dash of self deprecation can show that even though you have achieved all this you are still humble and grounded. This makes you much more respectable in a woman's eyes, and will make your value even higher. If you want examples of how trying to build value by talking about your achievements can go poorly, look at r/humblebrag. The cringe you feel is the same cringe a girl will feel if you start droning on about how awesome you are.

So, what's the right way to go about it?

Simple. Brag, then self deprecate. Talk about a way that you are awesome, then use self deprecation. An important note, don't self-destruct your accomplishments with self-deprecation. IE, don't tell her how you got this huge award at work, but you actually just nap all day at work. Further, your self-deprecation should be ridiculous. The difference between self-deprecating humor and a cry for help is whether or not you actually think it's true

An example of good self-deprecating humor: if you were talking to Bill Gates and he started talking about how he founded Microsoft, then was like "but I dropped out of college, so what do I know?"

It's funny because it clearly doesn't matter. Dropping out of college would not possibly make Bill Gates insecure because the dude could fucking buy Harvard if he wanted to. For a more relatable example, one that I use is about where I'm from. I grew up in Phoenix, but now live in Chicago. I will sometimes make jokes like "that's what simple people from Phoenix like me believe" or something. Because a) being from Phoenix isn't actually a bad thing and b) I don't even live there anymore so it's not like it's something that actually bothers me. No one's going to go "eh this dude is really fucked up from growing up in Phoenix" after that.

TL;DR Self deprecation in game is bad if you overuse it or it hits too close to home, but if used right can be a great tool to not look like an arrogant asshole.