Hi, actually it wasn't physically difficult. I think because I had rehearsed the act in my mind so many times and was ready, I was able to do it quickly and without thinking. Actually, the knife I used was an antique and super dull, and because it was a valuable antique I couldn't sharpen it or I'd ruin the pattern of the tempering, so I had to rely on the point and brute force rather than the cutting edge. It seems the blade also went naturally between my ribs as it was angled horizontally instead of vertically, so there was no bone resistance. All in all, the stabbing act was done swiftly.