Barbells tend to work best with intercourse for most, and they are in most cases the best choise for healing. So good choise!
It's best to see a professional for tge exact placement. Because of the scar, the placement you mentioned might not be possible. Most artist will gladly help you decide to make sure you will have the best healing and enjoyment. These consultations are usually free of costs and do not mean you have to get pierced right away. Take your time, think about it.
Frenum's are most often considered one of the least painfull male genital piercings and can heal quite quickly. Though, migration isn't very uncommon, I'm affraid.
One good thing to keep in mind to make sure your experience will be as pleasant as possible, is to find an artist you feel comfortable with and which you respect. Ask to see a portfolio if you wish, ask them to explain the procedure and aftercare. And hot unimportantly, ask about the initial jewelry. Eventhough in some states and countries, the usageof surgical steel in initial piercings is not forbidden, as a professional I'd strongly sugest implant grade titanium, especially for a frenum piercing. This because it's lighter and doesn't contain any nickle (a lot of people have allergic reactions to nickle, fresh piercings are even more prone to these reactions). Also try to make sure the lenght of the barbell leaves some room for swelling.
All in all, frenums can be relatively painfree, easy to heal piercings. As long as you keep respect for your body, why not adorn it? I'd say go for it!
