Does one pull out or drain your fertile nut deep

Ok...so you couldn't resist the urge to check out your phase-sis bare. It starts off off as playful sexual pressure, but then as her dresses start to arrive off... it will get pretty serious! Your brain is telling you this is not right, but your inner primal instincts will not prevent her as she begins to stroke your tricky cock. Before you know it, she opens her mouth, and you here feel her tongue close to your suggestion... then her legs unfold as she guides your throbbing meat into her swollen soaked vagina. It’s all occurring so rapid; you’re pounding her as she moans!! Your balls swell up with cum, and you simply hear your phase-sis say...cum inside of me! Do you pull out or drain your fertile nut deep inside her?