I'm going to do a messy night walk and I am looking for suggestions to make it top fun

I'd like ideas that aren't too obvious because I like the feeling of being messy under/inside che clothes but not outside, like hiding something with the risk of get caught

For the outfit the idea is a nike windrunner with an adidas tracksuit

Sounds like a great idea! Maybe I could pour it in the pockets too

Starting off with something like custard in your undies would mean there is the likelihood it would seep out as you walk around.

Sounds great! I'm not a big fan of custard but maybe I could use something else that will flow out as soon as I start to walk!