Gaining

Like the title says, I was wondering if anyone could give me se serious advice on how to go from 300 to 400. I've been stuck there for a little while so I would really like to get tips, preferably from someone with qctual experiences on gaining (or making someone gain) this much weight.

Just keep eating. Work on expanding stomach capacity. That will make you feel hungrier more often. Perhaps try starting off a day with a peanut butter sandwich. Very calorie dense, but, at least to me, not too filling.
Junk food is another obvious choice, but not too much, just more than you have before.

The best way to gain is to eat simply put. Always try and eat a little bit more than you did the day before. Try and pick the highest calorie choices available to you. Eat four full meals a day with some snacking in between whenever possible. Lastly try and eat as much of the food you do have while watching TV.

Another thing, eat late at night, then sleep. Goes straight to fat.
Also, drink calories. Milkshakes or juice, both high in cals and sugar.

Consistency is key, check how many calories you need to maintain your already curvy body.
So guessing your current weight 300 something pounds without any heavy work or exercise you caloric mainatnace is probably around the 3000 Kalorie mark.
So start to Tracking calories for a couple of days or weeks so you get to know the calories that are in food that you regularly consume.
Than make sure you eat above your need.
I’d say days that you can’t get the calories in by food have a shake. They can easily blast you in take.

If you're not already counting calories then it's time to start. I realize that many prefer not count them and enjoy the freedom of eating whatever they want but due to the high intake required to gain weight at 300lbs its pretty much a requirement.

You're gonna also want to figure out your maintenance calorie amount (how many calories it takes to maintain your weight), which you can find via google, and add 500-1000 calories on top of that.

If you're already 300lbs then I'm sure you've noticed that grazing is a much more reliable way to fit in calories than stuffing, as you don't really ever get full. Most supersized folk have a habit of constantly snacking.

Lastly start drinking heavy cream. 2 cups of heavy cream is over 1400 calories, so by drinking some at the end of your day you can really push that total daily calorie number. I recommend mixing it with some kind of chocolate flavouring (like a syrup or tasty protein powder) to improve the experience.