I could not find anything about it. What does it mean?
崇君は漫画ばっかり読んでてさ。
I could not find anything about it. What does it mean?
崇君は漫画ばっかり読んでてさ。
「読{よ}んで + て + さ」=「読んで + いて + さ」
「いて」 (てーform of the progressive 「いる」) is very often contracted to 「て」 in informal speech.
We say 「読んでて」、「見てて」、「食べてて」、「してて」, etc. You just cannot speak natural informal Japanese without using this いて-to-て contraction dozens of times a day.
Next, the sentence-ending particle 「さ」.
「さ」 is used to make a light and casual (and sometimes careless) kind of declaration. This sentence-ender does not have a clear meaning of its own. It is the kind of sentence-ender that some people use quite heavily out of a habit while others rarely do. Without exaggeration, some actually use it at the end of every phrase (or even word) like:
「あのさ、オレさ、昨日{きのう}さ、東京{とうきょう}でさ、トラブっちゃってさ、・・・」
In the real Japanese-speaking world, there is such thing as "one's go-to sentence-ender". Some go to 「よ」, some to 「ね」, some to 「さ」, etc. What type are you?
Here is an extremely famous children's song for you. Lyrics by a さ-type person.
The さ on the end is one of those mood particles that gets added on the end of sentences, like よ or ね or わ. The て is an abbreviated いて, the conjunctive or -te form of いる, so 読んでいて is the verb part of the sentence here.
Try proceeding from this point and see if it makes any more sense to you. :)