No sex for 6 weeks after delivering a baby, but what about just having orgasms?

Unless you had traum. Unless you had a very traumatic delivery, an ograsm should not cause any physical damage after child birth. If you had a c-section, then the contractions associated with an orgasm might be painful due to the repaired uterus. Even then, it is not likely going to cause damage to have an orgasm.
Go for it. Orgasms via any method other than intercourse and intra vaginal "toys" which can cause a post-partum fever if not clean, are "releasing" and harmless.