I increase my shaft size by:
- doing jobs at the motel
- pleasuring milfs from the disco, hotel or seldom gym
- making photos (excitement increase 30)
- making films (excitement cost 50 vs. excitement increase 60 from any "lucky" street girl)
From my perspective is filming a pov film (15 minutes) with your best actress and fitting toy in the gym the best way for increasing your shaft (by the way you can use/watch the film to increase your excitement).
Good luck Shorty