Father & Son’s Girlfriend

I know it’s overdone, but was looking for a RP recently where a teenage son (ages 17-20) was having issues pleasuring his girlfriend. Father over hears this and offers to help his son out...show him the ropes. Son would be present and would be asked to recreate technical parts that his Father demonstrates first. (The focus being in Father and Son pleasuring the Girlfriend)
After the first time, the girlfriend might be interested in having weekly tutoring sessions just to make sure the son is really improving. 
Seeking F character (girlfriend)