such a feat of articulation

Kspsht? Simplicity itself. Just start off with your tongue in the K position, pull it from the back of the mouth into the S hiss, whang the lips shut into the P, re-open with the tongue slipped back into the SH position and then finish off closing the sound off in the T position. Nothing to it.

Attually®, I think it's a copy and paste art(i,e)fact involving characters not printable in AWAD fonts. Which is not to say that I can't pronounce kspsht.