There is a lot of info available about finding the ventrogluteal. The only problem with most of that information, is that it's oriented for a nurse administering an injection. For those of us that don't have someone willing to pin them, this is what i found to be helpful for finding the VG.

The dorsogluteal (most common IM spot, part of your butt that you sit on) was my favorite goto for a while, but lately i've found that with increased muscle growth in my arms, shoulders and back, i'm not as flexible as i was before AAS and it's getting harder and harder to reach the syringe and push the plunger down without shaking from holding what is basically a complicated yoga pose. I'm not ready to start pinning delts or thighs, but i've heard a lot of good feedback on the ventrogluteal. It's not a muscle that is used primarily for walking or sitting so if you get pip there it shouldn't be as bad the pip you'd get in normal glutes or thighs. The hardest part about finding the ventrogluteal, for me, was finding the various anatomical features that a nurse would use to find the VG. The illiac crest and the greater trochanter mark the upper and lower bounds for the VG IM spot. For a nurse, the left and right bounds would be the distance between middle finger and pointer finger if they were to put there hand with the tip of the middle finger ont he middle of the illiac crest. Because it would be nearly impossible to situate your hand (for a right side injection you use the left hand with fingers pointed up to find the triangle zone) like that for a self injection, i had to find another way to locate the spot.

Someone recommended using the technique of shifting your weight, while standing, from foot to foot, the VG is the muscle that bulges during shifting. My problem with using this method was that while standing, my VG felt really tight, almost like a bone. And i was uncomfortable plunging a 1.5" 25g needle into something that felt that firm. So my solution was to sit down while self administering the ventrogluteal IM injection. If you are sitting down, the VG on me is almost exactly where your thigh and hip make a crease together. When sitting down, the VG is fully relaxed and you can easily feel the squishy texture of muscle beneath your hip. Also, sitting down forces you to inject more anteriorly (which is correct) than you probably would if you were standing up.

Long story short: sit down and the VG is very easy to find. I prefer to use a 25g 1.5" needle on the VG, it forces me to inject slowly. Hope this helps!