The “shun” sound in words is made with “gs”.  Open WordPad and type gs gs gs gs gs over and over.  Think “shun” as you type it, until you no longer (nlr) think G, S but think gs(shun) gs(shun) gs(shun) gs(shun) gs(shun) . . . .

abvgs = abbreviation
gngs = generation
dmgs = determination
dtgs = demonstration
admgs = administration
aflgs = affiliation
cbgs = combination
mafgs = manifestation