I used some 5cc syringes I had (marked up to 6mm) and a 21ga needle. Inserting the needle was virtually painless, though there was definitely a sensation as it entered the testicle. The sensation wasn't painful, it was almost vaguely enjoyable. I injected 3 - 4cc of the SL. At that point it was starting to get a little uncomfortable, but I knew I could have easily done another 2 - 3cc. I stopped because I didn't know at that time how much swelling I'd get from the SL.
Over the next week I did several more injections (only into my left testicle) usually in the 4 - 5cc range with one session of two 4cc injections for a total of about 21cc. There was never any pain and only maybe some mild discomfort for a few minutes following the injections. The swelling I got from just 21cc of SL was unbelievable, my testicle was the size of a small/med Russet potato! Here are a couple of pictures.


Due to out of country visitors, work, and other life stuff going on I didn't do any additional injections, and over the next 2 - 3 months, the SL dissolved and I was back to a basically normal size by the end of the year. But I wanted to try again, so early last week I did a small 3.5cc injection and on Friday another 5-6ccs. I was surprised there was a little bit of pain with the first injection, but the second was as painless as all of my earlier injections. Here are the results of about 9cc of SL.

I'll continue injections over the next couple of weeks as time allows and see where i get to; I know there must be a limit to how much a testicle can expand. And in case anyone is curious, I've had no changes in performance, or volume of ejaculate.
BTW, I much prefer the testicle injections over just injecting into the sac.
Best regards,
ChuckM