Hi toastanon,
Ugh, tampons suck. I personally use a
menstrual disc as my go-to period thing, but I understand that this option isn't available to everyone (I do recommend it, though)!
In any case, you're in luck; we have a few resources that should help. First, an ask column from a user struggling with the same issue:
Vulva, I Hardly Knew Ye
I'll put the bulk of the suggested instructions that Heather offers here, but I recommend reading the whole thing for added context.
It's usually easiest for people to start with tampons that have an applicator. One you have one open and in hand, you'll want to first relax. When we're nervous or anxious, our vaginas tend to clamp shut, and our vaginal openings get very tense, which makes putting anything inside difficult or painful (this is the biggest reason why women experience pain with intercourse, for example). Next, be lubricated: you can get some vaginal lubricant and just put a few drops around the vaginal opening, as well as on the tip of a tampon. Then, the easiest way for a lot of people with vaginas is to just put one foot up on a chair or the toilet. Using your dominant hand, hold the middle of the tampon applicator between your thumb and your middle or ring finger, and put the top of that applicator at your vaginal opening -- sliding your inner labia apart first if they're covering your vaginal opening -- with it tilted towards your lower back -- in other words, at something of an upwards angle. Then you just press the bottom of the applicator up with your index finger (or your other hand if that works better for you) until the tampon is in. If you fumble with this, doing it while using a mirror can help. But having really looked at your vagina before you try again may already make a world of difference.
I also want to add that tampons are
super drying (which makes sense - it's basically a sponge, after all) which is probably what makes insertion more difficult if you're are not used to inserting tampons. Therefore, the advice about
relaxing your muscles, adjusting your position, and using lube will help a lot!
Second, to help with naming and navigating the parts of the vulva/vagina, refer to this article:
Innies & Outies: The Vagina, Clitoris, Uterus and More
I'm unsure what you mean when you say "the back of your vulva." The vulva is the "outside" part of your genitals, comprised of the 'lips' or the labia, the pubic mound, the urethra, the clit(oris), and the vaginal opening. Basically, all the surface stuff. The vagina, bladder, and internal reproductive organs (uterus, ovaries, etc.) are the 'inside stuff', which is what I imagine you might mean as 'the back'? But you tell me. The Innies and Outies article has some helpful diagrams that might help.