I believe you'll find the night life in Santo Domingo very good. There is quite a bit to do, there's the cave bar.....that is probably the most reconized.....but in my opinion not the best. In general you'll find any type of bar you want and will not run out of choices......the closest place for a beach and a real good night life for a younger male is Boca Chica, try this area you'll probably really like it......check out
www.bocachicabeach.net for both areas ....SD and BC.....there is lots of information about both areas on this web-site......Have Fun!!!