@MindyLove
First off, there is no need to be embarassed about kinks. What helps you enjoy sex is perfectly valid. Despite this, it can be hard to bring something up with a partner because if they are not interested it can leave you feeling bad for bringing it up, or leave them feeling like they are unable to do what it takes to satisfy your sexual needs. As someone involved in the BDSM community I strongly empathize with how difficult introducing the idea to new people can be. When beginning a conversation with someone like your boyfriend, who takes things very slow, the idea of BDSM might be a bit overwhelming. If he is most comfortable taking things slow, perhaps you could introduce the idea slowly. If he is not comfortable talking about sex, maybe you could ask him - durring sex - to do something he is already doing a bit rougher (for example, if he is on top and puts some weight on you, you could tell him you enjoy how it feels when he is pinning you down like that and he might feel encouraged to do it in a more direct way). If he does something that you enjoy, make sure to give him a positive response! People like to know when they are doing well, so if you give a lot of positive reaction to rougher activities he may start to initiate them. When you are having sex, and in the moment, that is the easiest time to give him small cues to be rough. Once you have gotten him used to doing the things he is used to in a more dominant way, you might be able to introduce new activities such as scratching or slapping. Of course, maybe he just does not enjoy being dominant. Not everyone does. But you can only really find out by asking him or by trying to see if he gest excited when you encourage it.
I would also encourage you to keep trying to talk with him about sex. Open communication is very important to establish in any sexual relationship. One of the easiest times to talk about sex is right afterwards or tight before. Things like telling them something you particularly enjoyed, asking them to do something they did last time, or asking them if they liked something you did, can help him feel safer talking about sex in the future.