#showtooltip Wind Shear
/cast [target=focus,exists,harm] Wind Shear
/cast Wind Shear
What it does: it will cancel your cast, check your focus target and a)remove focus if target is dead b) cast windshear ion focus if the target is hostile c) if you have no focus or your focus is friendly, it will cast windshear on your current target. the showtooltip line is so it shows wind shear icon.
to my knowledge there is no effective way without addons to do a successful stopcast macro with Lava Burst because if GCD is still active it will not cast the LvB and just spamming it will keep interrupting your LvB however you can do one for flame shock to ensure you don't let it fall
#showtooltip Flame Shock
/cast Flame Shock