Toad isn't doing anything to intentionally trigger p00x parallel queries. The database decides if it wants to do stuff in parallel. I am not sure if OCM has anything to do with that or not.
However, Toad may make some connections in the background for various tasks. It might help if you configure Toad it to not do that, and do everything in one session. See the following on how to do that. Let me know how it goes after that change.
Toad does execute a big pl/sql block when a connection is made. We've done our best to keep that executing as quickly as possible. Normally it should take just a second or two. But I wonder if something in there is what is causing the delay and all the parallel queries. Maybe turning on spool SQL in Toad before you make your connection will give some clues (database -> Spool SQL -> Spool to screen).