On average, how much fat can be removed from the mons pubis during a liposuction procedure?

 It's very unusualTo remove more than 50 mL or so from the Mons. However in patients with a high BMI it might actually be more than this.

For any patient with a significant weight issue, the first step is to maximize your weight loss. Then liposuction combined with a pubic lift (to deal with the excess skin) can really make a difference in penile show. It may be possible that liposuction alone is adequate but this would be uncommon when there is weight loss involved.