Cum bomb directly into my step-sister’s open fuck-mouth

This perverted, dirty idea is mine this time :). My little step-sister is usually known for coming up with the craziest and most perverted fuck ideas. But this time I’m in charge. The idea: My little step-sister lies on the floor with her fuck-mouth wide open, her wet cunt waiting for the cum bomb that’s about to squirt down from above. The guy is kneeling above her with his balls full. My job is to empty this ball to the last drop so that my little step-sister on the floor gets a mega shower of cum in her mouth. To achieve this, her cock and prostate must be properly penetrated.