Ummm... So I am a female but I don't think you will get a disease. That involves two people.
Great job the safest kind of sex to have and no drama
Okay, I'll take the bait to make one different, salient point. Of course a man cannot give himself an STD with his own ejaculate. Wallow in it, smear the body with it, swallow it---all makes no difference; it comes with no infecting outside contact from within his own body. But I'm curious: If everybody is asleep, it must be nighttime, so why do you afterwards "put [your] clothes back on"? What is the importance of your "never [having] been naked before on [your] bed"? What's your age? You seem to have known about, and eschewed, masturbation and orgasms for a good while...thus is seems odd that you would suddenly decide you wanted to masturbate for an orgasm. ~~~ But my salient point: It sounds odd to me as an intact (uncircumcised) man that you would PULL your foreskin for stimulation. Personally and anecdotally I have observed that intact men almost invariably RETRACT the foreskin to achieve erection and stimulation. Circumcised men almost invariably PULL on the penis to achieve those effects. If you are so new to masturbation, you might want to try retracting instead of pulling. Just a suggestion.
There is no risk for std's from masturbation. We also, just want you to know, do not need full graphic description of what happened. masturbation is normal and not a big deal.