When I stand up a very watery grayish discharge comes pouring out my vagina?

See below. If it could be bacterial vaginosis especially if has strong odor. See your doctor for a pelvic exam to confirm.
OLD SMELLY TAMPON! Most likely you left a tampon or foreign objects gway up in the vagina for weeks or month! have mercy! please see your obgyn to check it out asap usually its so high up there and lying sideway that you can't reach for it yourself please let me know if I am correct! good luck.