How do I detonate C4?
What is the default control for detonating C4 with a mouse and keyboard?
I missed the tutorial, it's not referenced in the options or keybinds, and I continuously forgot how to do it.
Solution 1:
To detonate C4, hold Aim (RMB by default) and simultaneously hit Use (E).
As mentioned by @Lucas-Leblanc, this also works with any of the other 'trap' items, such as the Decoy Mine.