Do you guys know any sweet and cute yaoi mangas? I seem to be coming across a lot of dark ...

Kiss Made Ato 3 Senchi. I found this one comparable to wool... Soft and fluffy, but too much contact can cause itching.

http://www.mangago.zone/read-manga/danshi_koukouseiteki_kazoku_keikaku/
http://www.mangago.zone/read-manga/kokoro_kanda_neko/
http://www.mangago.zone/read-manga/twinkle/
http://www.mangago.zone/read-manga/nirameba_koi/ (a little more serious cause there's some fighting, but still cute)
http://www.mangago.zone/read-manga/jackass_sawatte_ii_tte_dare_ga_itta_yo/ (also a bit serious cause one of the guys is a bit of a kinkster (it's not too bad, I promise), and the other guy is iffy on it and- but the story has some pretty light hearted moments and can be pretty funny).
http://www.mangago.zone/read-manga/sono_koi_ni_wa_wake_ga_aru/ (One of my favorites, not quite 'fluffy' but I adore the uke because he tries so hard to be tough (cause he is, really) and his interactions with the seme really warm me up).

http://www.mangago.zone/home/mangalist/211822/

I just finished rereading the Kokoro series of kanda neko. Adorable and funny. I recommend reading it if you haven't yet. But even if you had, I still recommned it. (⌒▽⌒)

There's one on there called 19 Days that I should have put on my list above because olakdfaisfdk it's fucking wonderful. Don't let the chapter count or the first couple chapters fool you- the chapters are super short (about 8 pages, maybe less), and the first couple chapters are just pictures and whatnot. And the story is a bit wonky at first, but seriously,check it out. It's hilarious, there were parts I was literally laughing at, and the further you get into it, yes, it gets more serious, but it also gets more sweet.