The ninja rest ambush should be available in the forest after you clear the mountain(beat Nara 1st time) and before you beat her in the temple, now i'm not sure if resting and therefor getting the fight to start in the sex stance matters or not.
The titfuck starts as a counter attack, you'll see something like "her eyes are glowing" on her turn and that means that if you attack the next turn she'll counter you with a titfuck+energy sap combo which is actually pretty tough, this should lead to a titfuck and back to church scene, same should be true of the BJ, there are additional scenes for her main fight in the temple but by that point her name should be visible rather than just "Kuniochi.
As for beating her in the temple, use analyse to check the HP, if it's 75 or so it's the clone, just leave it be and check one more, by elimination you only need to waste two turns on that, just be careful not to KO a clone or they will shuffle and you'll have to check again, after that it's quite simple tank and spank, bring some anaph herbs, insomnia items and steer clear of counter attacks, also teleport if you have it is the best escape move against a group, something you may want for double teaming the bosses latter in the temple.
Oh and unlike other bosses she has the perk that means she heals if she makes you cum so max HP matters more than spirit in this case, consider turning off any the Sophia perk that boosts spirit of you have it.
In my experience the problems occur when they stack stances on you, multi BJ and multi titfuck are hard to escape, increasing tech helps your chances of escaping stances so consider equipment that raises that, also remember to get the goddesses blessings, by this point in the game you should have some spare gold that you would throw her way via the donate option.
