How do I tell my bestfriend this?

My bestfriend is 15, and already has has sex with 5 guys since she was 14. I’m not judging her in any way, but shes not being safe with it.

She doesn’t use condoms, no birth control, hasn’t been tested for std’s or anything, and all she uses is the pull out method.

How do I explain to her that this isn’t safe without upsetting her?