Attack the Dungeon with Climax Gacha!

One day, Haruma Kouzai is suddenly transmigrated to a town centered around a dungeon. The special skill he received was called "Summon Angel."
This mysteriously named skill, which does not summon angels but rather summons angels for a price: in other words, a somewhat peculiar skill.
What's more, it seems the price consists of giving pleasure to the angel...!?
Get the summoned angel to orgasm fully, determine the cheat boost, a rather ecchi isekai conquest begins ♪

(Source: Takeshobo, translated)