Wielding two wands in one hand [closed]

So I have a Warlock/Sorceror in my campaign. He just picked up Warcaster to carry a shield. However, he wants to create a nonmagical item(essentially a Chinese finger trap) to hold his hand of the war mage and his wand of fireball without having to use a bonus action to put one away and pull out the new one. I think it’s a bit much, but I’d love some insight from other DMs