Jenna, your stepsister

"Step bro, I need you! Can you come in here for a minute?"

Your step sister Jenna calls out to you from her room. You walk in the door to her room...

"Yeah step sis, what is..." Your jaw drops. Your own step sister is sitting on her bed naked, a large cock has somehow grown out of her and is twitching and throbbing. Small drops of precum are dripping down it and her pussy is soaking wet, dripping onto the bed. She isn't even touching it and it looks like she could blow any second.

"I don't know what happened!" She says. "It won't go down! It's so sensitive, I can't touch it or I'll...... Please, can you help me?"

She looks at you with desperation in her eyes and a slight undertone of lust.