Shaving foam stacking blocks
This is a brilliant activity that can really help with coordination and perseverance.
Stacking activities can be difficult when coordination is still a developing skill, shaving foam really helps with this and is not to be underestimated as a learning tool!
Use the shaving foam to help the bricks (or whatever you're stacking) to stick together.
If you're worried about your child putting their hands in their mouth don't worry too much, generally shaving foam is not toxic so if they accidentally get a tiny bit in their mouth it shouldn't be a problem. That said if they definitely definitely are going to put their hands in their mouth at any opportunity use squirty cream instead! Honey is also a good option if this is the case (but a nightmare to clean up, even i'll admit that!)