The first manga that crosses my mind when seeing your question would be Golden Sparkles. Quite Hard to find such Uke but if you search deep enough, you'll find it.
Thank you very much!!(≧∀≦)
http://www.mangago.zone/read-manga/golden_sparkle/
Yep, he's one of the best pure ukes I've seen in a while. He's straightforward and isn't afraid to face a problem head on.
I'm not sure what you mean by "pure" but if you mean virgin kinda thing imo, hxh roman company (first pair) and tight rope has a cool uke. I dunno what you find cool though so I'm sorry if this doesn't meet your expectations!
Golden sparkle is freakin good btw
Is there anyone who knows any yaoi manga
With cool but pure uke? (づ￣ ³￣)づ
Sorry for my bad English... (￣∇￣")