So if you're learning Japanese, one of the single best things you can do to improve your Japanese is to make a whole bunch of close Japanese friends.
With no further ado, I want to introduce you to 3 websites that I know of.
Interpals is a great site that'll let you have 1 on 1 text conversations with a lot of people from around the world. The Japanese population here is quite signifcant and in no time at all, you'll be having all the conversations you can handle.
Don't be shy to just throw out a "こんちはー" to whoever piques your interest.
This is a GREAT site for people who want to observe some native Japanese social interaction online without having to participate themselves. Sometimes, I'd just lurk and watch. I found it difficult in my early days to really keep up but it was a great place to just get raw exposure and I'd also go around and find dead channels with no viewers and just chat with the host. Click on 新着順ライブ (shin chaku jun raibu - sort by newest) and it will bring up all of the newly initiated streams.
By the way, "CAS" is just the キャス in ツイキャス. I guess it's short for broadcast now that I think about it.
I'm going to teach you a useful expression that they use here: "初見です！" (shoken desu)
This means something like, "Hey, it's my first time in this channel" or "Hey, it's my first time viewing your stream!"
It's a really natural expression that you'll see a lot here or on places like YouTube live streams, etc. and if you say it, I expect you'll get a variation of a pretty hearty "(your name)さん、どうもいらっしゃい"
The viewers don't tend to talk directly to each other much, (depending on the person ofc) but here's a nice little expression you can use when everyone's going to sleep (since you'll likely be on a different sleep pattern):
落ちる方、お休みです (ochiru kata oyasumi desu) = "Goodnight to all the people heading off"
This site isn't the best place to take friends away, back to whatever instant messaging program you use, but if you find yourself a regular streamer who has a small following of a few regulars, it can be a great place to relax and practice your Japanese in a group setting.
Some people watch Twitch or Youtube streams and these are all well and good but Twitcasting is primarily for chatting and socialising online which is what you're after. There are game streams on here, too though, and people do live Karaoke among a variety of other things.
So, we have something for groups and we have something for one on one text chatting but the only thing we're missing is a good place to find people to voice chat with.
This is my secret weapon. I don't have many followers so the few who are interested in learning Japanese and followed me for Japanese content, I'm going to share with you this little gem. It's a place where you can find people who are just llooking to have a conversation. Some people are asking for a light chat before bed, others just simply for small talk. I imagine a lot of these people are introverts, possibly lonely or with few friends who are just looking to socialize in a comfortable setting. So this is gold for Japanese learners in the intermediate stage who are looking for practice since I don't think many of these people will mind if you make mistakes, fumble your words, can't get anything to come out of your mouth or even if you're broken.
Now, this is native only, which is what I meant by it being my secret weapon. The Japanese language learning community doesn't know about this place and you can't go around spreading it on the internet otherwise you will destroy its purity.