If you don’t want to mess around with pitch envelopes inside the sampler, then don’t forget about the humble pitch slide commands.
A simple D80 over a few lines will give a pretty rapid pitch slide down. You can play with different values to slide faster or slower, change the effect over time, etc.
Obligatory quick demo:
6783 dblue-2016-06-17-tapestop.xrns
(Sample loop courtesy of the Music Radar B-Boy Electro sample pack)