You mash a banana in a jar of peanut butter, proceed to stir it around with your penis.
You then use your penis to spread it across her face like a butter knife. This should satisfy both your needs at once.
Jacob: I want a blowjob. Give me that jar of peanut butter and a banana.
Jacob: You're getting the Elvis Presley, Beeoch, I hope you don't have a peanut allergy.