I use this term ALL the time with my sissies. And recently, I have had a few people ask me what exactly I mean when I say sissygasm...though I think they just want to her me talk dirty!!
But since it is such an important concept for all sissies, especially those in chastity, you can listen to me explain it HERE.
Thank you, Mistress Sierra! I practice my sissy pussy penetration with my manly dildo but haven't achieved a sissygasm yet. I do try to touch my clitty only through my panties and in swirling circles. That combined with taking a nice big cock like a proper sissy slut, I do cum very hard.
Guess I need to keep practicing.