Corner ground hk throw into s.lp+Storm s.hk (one hit) xx MT - works on Cable, Capcom, Psylocke, Cyke, etc., pretty tough on Magneto, pretty much impossible on Storm
ROM into corner (put them low), land, s.lp+Storm s.mk xx MT
OR
ROM into corner (put them low), land, s.lp+Storm s.mk HG xx MT (exceedingly hard to mash and gets you more hits than the previous setup) - both of these work on Storm, Psylocke, Capcom, NOT Cable, maybe Mag
The faster they get hit after being captured by HG, the harder it is to mash out. I haven’t done it in a long time but that last combo, I think, has the Typhoon hit them almost immediately after they get grabbed, and then the rocks combo from the Typhoon’s hit stun.
EDIT: No, the HG actually grabs them right after they bounce off the Typhoon. In any case, there’s very little time to mash out, and you can usually juggle them afterward with c.lk c.hk if you haven’t already done so in the combo.