I've had this happen. usually what triggers it is going home early and sleeping the day away with your sister. she just suddenly get out of bed missing her panties. if you ask her what panties she is wearing tho and she says none its not glitching. if she say white etc then it is glitched. usually if i upset her just like a real woman she put her panties back on. also after the bath or shower she will correct it too when it happens to me.