Bondage means tying up or being tied up by your lover. This can be (part of) a sexual game you play with your lover to add to the sexual excitement.
The one who’s tied up is in a vulnerable position, unable to do anything.
Some like to be helpless and being forced into submission, while others prefer to have control and orchestrate the lovemaking session.
When you tie up your lover you can do this very seriously: no escape possible. But you can also simulate it, tying up the other in a playful, symbolic manner.

Safety measures

He went too far