Anything long and round works. Picked up a trick from a post on LPSG I saw years ago.
Find your long & firm object, tightly wrap toilet paper around it until you have your desired thickness and pop a condom over that. TP makes it soft and pliable enough for comfort, but it's still thick and rigid enough for play time.
Had to go to Saudi Arabia for work & obviously couldn't take a dildo with me, but turns out they're fine with condoms (surprised me, tbh).
Tried that trick with the handle of a hairbrush and had a GREAT evening.