Dramaqueen

STDs are not likely to be transmitted through mutual masturbation but here's a list if you want to know:

STDs spread by FLUIDS:

Gonorrhea, Chlamydia, HIV, Urinary Tract Infections/ Nongonnococcal Urethritis, Hepatitis B (HBV), (Hepatitis is also found in saliva, so kissing is a risk), Syphilis Cytomegalovirus (CMV), Trichomoniasis (Trich)

STDs spread by CONTACT (skin-to-skin):

HPV/Genital Warts, Herpes Simplex Virus (HSV), Molluscum Contagiosum, Chancroid, Syphilis, Crabs/Pubic Lice, Scabies

I do't think you need to use a condom with a handjob, but with oral sex and intercourse definately.