you can actually do it on mobile :D (tho it doesn't work all the time)
For a superboop, press down for a few seconds, then press down again on the "boop" button. It'll change from boop to super boop
For an evil boop, just do what you did for the super boop but press on the button for longer. It appears after about 6 seconds of pressing or so
tumblr not allowing super and evil boops on mobile is diabolical