Buy yourself a merengue soda drink from the local store. It's amazingly good. You may also want to try the red soda, just say Rosa pop to the store owner unless you know Spanish well. If you can't find the store just find those sodas somewhere! I'm sure you can find them anywhere on the island.
I went through my HS twice for 8 days to Cruz Verde, DR to volunteer with the Sister Island Project. Peter and Victoria started this project and have a website you can google. We stayed one week but there are other options such as a two week stay where you also help out in construction. The one week stay is helping out with local youth group teens at an arts and crafts camp for children of all ages. We stay with host families in this semi poor, very small town and experience the culture that awaits us. Activities are set up each day such as 3 days helping with the camp, 1 day at boca chica beach and santo domingo, 1 day of your choice of activities such as making chocolate or riding horses etc, a rest day or 2, and the last day we have a fiesta and disco which is a LOT of fun. I learned merengue and salsa and bachata. I made so many friends especially young children from the local town. They love playing with us and other volunteers and teach us games like dominoes and hand clapping games and some songs too. It was so much fun and I recommend helping out their project. You can find out more information about it on their website. There is just too much to say about the trips but if you DO decide to help them out just prepare yourself for mango eating and a LOT of dancing. Also it would greatly help if you knew Spanish.
PS: if you go and volunteer, make sure you talk to or find welinton or omar, the coolest dudes in town =)
I would either get to know a local with a motorbike or bicycle, car if they have one and if it works which is rare...or get stuck walking everywhere.
Basically wherever you go in the Dominican Republic there will be music or dancing. Mainly bachata, merengue, salsa...one popular pop song is La Bomba by king africa. Youtube it. Most of the music has a significant beat to it and many use drums in the background and sound almost tribal but always danceable. They do different dances to some songs like we have our macerena or souldja boy. Discos are very popular.
If you choose to go during the summer or mainly the rainy season, you chould be aware of the mud and puddles...as in there are a lot. Most of the roads are dirt. Also, there are plenty of bugs/insects. Besides the mosquitoes, be aware of cockroaches, large spiders, and red ants. Most of the locals though are more afraid of the frogs and toads that come out during the night than the spiders. Most of the spiders will run away and won't hurt you but just be careful around the variety of insects that you do come across.