Take 6 needles, one block of wood, a hammer, and some nuts

 I am a dab hand a many things, being a surgeon the latest of my new found professions. Mr. Zena does all the building  of bits of equipment for the facility, and I want a piece of the action. But first I must learn the intricacies of carpentry. I know, how hard could knocking a few nails and sawing  bits of wood be! Mr. Zena insists that I do my apprenticeship properly. But this is me we are talking about, I do things, how should I put it, a little differently. So I must practice my hammering skills first. I need something someone to practice on. Out goes the call and in come the offers, who would think that what I had in store would create a scramble  to be the "honoured" one to assist me. My chosen victim helper in my workshop is @paindeamon, he has no fear, he has no brains. lol
Now just to make sure he doesn't chicken out at the last moment I tie him securely to the banisters, legs held open with spreader bar, hands clamped together with cable ties and strung up to the light fitting with wire. There, that should keep him from squirming about. I place my block of wood under his ball sack, this process in itself makes beads of sweat form on his forehead. For the technically minded of you, I am using a ball peen hammer and 21G hypodermic needles. The wood is soft pine, very good at mopping up blood, see I think of everything. Sitting down on the floor in front of him, I  get comfy and get his ballskin nice and spread out, so I can see what I'm up to. I don't bother to drag the moment out, building the tension etc. I'm way too excited. Needle out of its case, gently pushed into skin to get the initial 'purchase' a brisk 'tap tap' knocks it home. No resistance from his nuts, so the wood stops the needle. A third harder tap from a carried away carpenter gives a slight bend to the needle. No problem, we laugh that off! Over to his left nut, spread in the same way, nailed to the wood with symmetry without bent needle. I continue until I've used all my sharps and spare ball skin. So I sit back and watch the small amount of blood gently ooze onto the wood. He's relaxed, happy with the situation actually and impressed with his performance-as am I! Good, I'm gasping for a coffee, had no caffeine for a while in case of 'shaky hands' that us surgeons fear! You sit there and bask in your needle 'high' I'm putting my kettle on! O.k time for removal-out they come & into sharps box. Dressing held firmly to the affected area, made him smile, gave him a stiffy-yay he's back to life already. Go on-I'll untie your right hand, make sure he still works.
There, I am proficient in hammering, now where is that saw!!