you dont want to IM anything UNLESS you have a micron filter. all the cuts will just sit under your skin making for a perfect environment for bacteria to grow (abscess)
im sure plugging would suffice, you wont get a rush like IV, but it will hit you pretty quick. however, if you are a daily frequent opiate user your anal cavity is probably all backed up. another solution would be to dissolve in water, lean your head back, and slowly drip the heroin solution into your nose (waterlining)...but if you are already going to IM, why not IV it? plugging or waterlining is definitely the safer option, but some people are bent on using needles.
the only time i IMd something was using micron-filtered buprenorphine solution because IV bupre lasts only 8-12hrs and IM buprenorphine lasts more around 24hrs.
edit: good god, get yourself to the hospital man! you are in a life-threatening situation. time is crucial here...are you bleeding? if so you could bleed out in under 5mins.
seriously, if you are fucking set on doing the H, get someone to drive you and brg the dope in the car. brg a spoon, water a lighter and an oral syringe. put dope in spoon, add water, heat for a second (it is okay to heat it a little because your rectum will filter the cuts). then draw up with an oral syringe, lean to the side and stick it 1/4 of the way in and plunge away.
that or call the ambulance and while you are waiting do the dope.
PLEASE PLEASE PLEASE hurry and get some medical help! if you wait too long you wont even be able to ever do dope again because you will be dead.