How to Give a B12 Injection: Step By Step Instructions How to Self Inject Vitamin B12 at Home The Sanctuary Wellness Institute Figure. Subcutaneous injection into the deltoid area The Australian Immunisation Handbook Subcutaneous injection technique HOW TO GIVE A SUBCUTANEOUS INJECTION Make sure the skin clean, dry, and without wounds Injection sites Position the syringe dominant hand Gather mound of skin between hngers Insert