I worked on this for my book project (still lumbering on) but couldn't wait to share it. The version of the mantra I'm commenting on is the one in the FWBO Puja Book.
On the 12th of Dec I'm running a workshop at the Cambridge Buddhist Centre where we will study the Sanskrit text and then chant the mantra. Book online by visiting the CBC Website.
Happy Halloween - the Vajrasattva mantra is just what you need to keep the ghouls and ghosts away!
oṃ vajrasattvasamayamanupālaya vajrasattvatvenopatiṣṭha dṛḍho me bhava sutoṣyo me bhava supoṣyo me bhava anurakto me bhava sarva siddhiṃ me prayaccha sarvakarmasu ca me cittaṃ śreyaḥ kuru hūṃ ha ha ha ha hoḥ bhagavan sarvatathāgatavajra mā me muñca vajrī bhava mahāsamayasattva āḥ