[沙悟荘] 絶頂勇者

Or At the height of the Valiant according to Google Translate. The back of the doujinshi has it as Sago-Jou presents Brave - XTC. Whatever it is, this is all about female Loto from Dragon Quest III (sorry, "female Erdrick" just doesn't sound right...) who now seems to be rather well endowed.

Sago-Jou - Brave XTC
Artist's website