You can get this in the video tape portion, while doing the Wrecked Ship area. You will eventually come to the remote bombs. When you do, go ahead and just choose to "retry". Now, run past the first enemy and kill the second. Grab the bombs and lure the enemy into the hallway. This can be an extremely frustrating achievement. The monster will either slash, or grapple you. If it grapples, it will either bite your arm (which happens most of the time), or it will push you to the ground. When this happens, you will need to press RT to resist. This will plant the bomb inside of the mouth of the monster. Now press X to blow it up.

This can be done on any difficulty. It may take several retries. Try to keep a medium distance so that the enemy lunges instead of strikes. If you are close and it strikes, remember to just block it. It's possible the reason it bites more is because often, your character will have the watch out. Equip your knife and then equip the bomb again so that it shows the bomb and not the watch (if things don't seem to be going your way).