Do not use soap in your vagina. Don't use anything in the vagina. It's self-cleaning. The discharge you get throughout the day? That's how the vagina cleans itself. Using soaps
will only put you at higher risk for developing an irritation or infection.
Just using warm water and a clean hand is enough.
Vagina = internal
Vulva = external
It is possible that using soap to wash your genitals with may be causing the irritation - drying, general irritation, or infection. Your vagina is self-cleaning, discharge cleans out dirt and dead cells, the vagina is also acidic so kills off harmful bacteria while allowing healthy bacteria to thrive, you needn't do anything to clean your vagina. You need to clean our vulva, but you do this water only - when washing use your hands to wipe away dirt from between the labia. Soaps or washes are completely unnecessary and potentially harmful.
All your genitals ever need to stay clean is water - anything chemical; soaps, washes, wipes, and feminine washes will all potentially kill off healthy bacteria and effect vaginal pH so cause increased growth in unhealthy bacteria and yeast in your vagina/vulva causing odour and infections. Feminine washes are just as bad, they will never match vaginal pH, least of all your individual vaginal pH or the pH as it changes throughout your cycles or day-to-day - these are made to make money out of women's insecurities about their vaginal odour, they're just as harmful as anything else.
Bear in mind too that your vagina/vulva is made up of mucosa - like skin but without the top protective layer - this is why soaps/washes on your vulva is potentially harmful too, this is because mucosa is more sensitive so more prone to irritation from chemicals in soaps/washes, soap/washes are drying which will dry-out mucosa, and many washes contain harmful ingredients that are more easily absorbed into the body via the mucosa.
Washing Your Vulva & Vagina: Soap Isn't A Friend At All.