Dating multiple girls I'm not going to get into my opinion on the morality of it all, because I'm pretty old-school and I'm sure you don't want me preaching to you! Lol! However, I just finished teaching a sex ed unit to my kiddos, and let me remind you (or inform you, if you don't already know it,) that condoms do not always work against some stds. The reason is that condoms do not cover all of the skin "down there". Some stds, such as herpes, are spread by skin-to-skin contact, therefore condoms do not always work. Furthermore, some stds have the ability to lay dormant for months or even years before being detected (herpes is actually one of them.) Keeping with the herpes example...contrary to popular belief, you do NOT have to have an outbreak to spread herpes, and, though medicine can keep outbreaks at bay, herpes is not curable. Then there's the fact that condoms can break--leading to other diseases, pregnancy, etc. In short, the more partners you have, the greater your risk.
Dating multiple girls ^^^ All of these. Be up front and make sure there is clear communication and that boundaries are set. Use a condom and get tested regularly.