it´s no rape when a man like it what a monstergirl do with him or his it´s own free will to have sex with her. too when he know what happen when he decided to marry a monstergirl or live with her together. when the profile say she never let him go but the man want go back to his home he can say: if you really like let me go and come with me! the most will monstergirls accept this offer but it´s adifficult thing with seamonsters and plantmonsters.
if i weren't for the fact that you have to get drunk, i wouldn't mind being captured by a blue oni. the thought of being able to make her blush seems really cute.
when monstergirls organize drinking parties maybe others arrange sex parties and invite humans and monstergirls to her party. for these who are only interested in sex with humans is this no problem.
... This sounds like a typical Summer to me, well, asides from it not being really rape' per se, as I am more than willing to submit to a good looking girl.
If only Ao Oni was about these kind of Oni chasing you and hunting you down, instead of the crazy freakshows that persistently stalk you all game long.