How do I discipline my kid when she thinks getting in trouble is funny?
Children often try to increase their level of control, power or influence over a given situation. A child may laugh when getting a consequence as a way to try and unsettle you or gain back some control in the situation. If they think that it might make you second guess your punishment or make you feel like what you are doing isn’t impacting them, then they win that battle.
If you remember the saying “never let ’em see you sweat,” that applies in this situation. Stay strong and stick to what you said initially.
Planned Ignoring is the strategy that is most helpful in this situation. You do not look at them, talk to them, or react to their behavior. If you have to interact, simply repeat the instruction like a broken record. No yelling, just firm and clear. This is very difficult to do when you feel like you are being taunted. However, an irritated, angry, or exasperated response is really what they are looking for (either that, or they are hoping you will change the punishment to something else). Stay calm and stick to your punishment as you stated it (it is important to do what you say you are going to do).
Then, to yourself, think about if the consequence you chose is something that is meaningful to the child or not. If they truly don’t care about losing whatever it is, then choose something different the next time, something that will have more impact (e.g. loss of screen time, change of bedtime, adding a chore, or missing out on a fun opportunity).