ABARENBOU KARESHI, try all manga by junko and yamamoto kotetsuko sensei
Well, i can say i had read a bunch of yaoi manga but kinda forgot the title..
If i can suggest you about fluffy and the seme kinda sweet/beauty, here is (maybe you had read it, so sorry):
■ Harapeko Usagi (by Kanda Neko) http://www.mangago.me/read-manga/harapeko_usagi_to_koisuru_ookami/
(all Kanda Neko's art really beautiful, just check her other mangas too)
■ XXX Alergy (by Hinohara Meguru) http://www.mangago.me/read-manga/xxx_allergy/
(There's the sequel too)
■ Miwaku Shikake (by Nekota Yonezou) http://www.mangago.me/read-manga/miwaku_shikake_amai_wana/
(The seme so beauty, he was called 'Queen')
■ Danshi Koukouseiteki (by Umniyuki Lily) http://www.mangago.me/read-manga/danshi_koukouseiteki_kazoku_keikaku/
■ Yondaime (by Scarlet Beniko) http://www.mangago.me/read-manga/yondaime_ooyamato_tatsuyuki/
(My fav of scarlet beniko's, the seme look kinda dull, but he's so sweet, so strong and hot. Check her other masterpieces too)
And there's more but i kinda forgot. Hope this useful for you (⌒▽⌒)
Honto Yajuu was the first one that came to mind :) Fools is a fluffy manhwa but the progression of the otp is VERY slow if you're fine with that!
Can anyone recommend a manga with a cute and sweet seme? I just need something fluuffy u kno??