What are you top 5 items to fill your underwear or swimwear with?

Mine are:

Custard
Angel Delight
Spaghetti in Sauce
Baked Beans
Porridge

These are ones I've actually done:

Mayonnaise
Chocolate pudding
Gel shaving cream with menthol
Goopy bars of soap
Tube of toothpaste

thumbtacks
scorpions
medical waste
a grenade
your mom

an umbrella (unfurled)
copy of "War and Peace"
a baited mousetrap
glass shards
an 8x11 signed headshot of Bea Arthur

liquid nitrogen
live eels
old man farts
feelings of inadequacy and despair
a basket of deplorables

can of frosting, then just go about your day, walk around the stores, bend over and tie your shoes, etc

I once put a large jar of mayonnaise down a pare of sawed-off rain pants and sealed the legs at the crotch with some tight elastic. Then I went for a run around some busy down-town sidewalks, making eye contact with everyone I passed wondering if they could hear the squishing sound clearly being made by all of that mayonnaise. It was quite exciting, especially knowing that it could have sprung a major leak at any time.

Rice pudding
Semolina
Baked beans
Tinned spaghetti (the long stringed type)
Porridge/oatmeal

On the sweet side:
Custard
Syrup
Whipped Cream
Rice Pudding (tinned)
Ice Cream

Savoury:
Eggs
Baked Beans
Pancake Batter
Spaghetti Bolognese (tinned)
Mayonnaise

Sounds like i'm going to have to try mayonnaise. I'd imagine it feels great although it may be rather smelly. We have large buckets of it at work that i've always dreamed of taking home.

Syrup sounds good too.

Anything warm,

Oatmeal, warm cake batter Hell ya!

Of things I've tried:

Whipped cream
Chocolate sauce
Natrosol
Shaving foam
Water crystals (hydrated)

Mmmmm yeah. I've done warm oatmeal/porridge before.
I completely forgot it was still warm so it was a pleasant surprise when it hit my bum!

Pudding, oatmeal, Yogurt, cake mix, eggs.

But I would be willing to have most substances in a speedo or my briefs.