Something I've been having success with lately:
When you have Killing Machine active and you land a combo, end it with d2. Then, if you have time before falling asleep, immediately throw out Ex-DB2. The d2 is a great ender for Slasher in general because it is one of his most damaging options (F42, F42, F42, D2 does 34%). Additionally, it also places opponents far away, which is great for minimizing their punishing potential once killing machine runs out. And, if you have time to throw out the enhanced machete toss as a meaty, it forces them to block or eat the machete, which by the time they do, will leave most characters with limited punishment options before you wake up again.