Here's why and some options depending on the context:
1. It's context-dependent:
* "Hold my beer" (meaning "watch me do something crazy/dangerous"): There's no single, equivalent phrase in French. You'd need to explain the situation: "Regarde ce que je vais faire!" (Look what I'm going to do!), "Je vais essayer ça!" (I'm going to try that!), or "Tenez-vous bien!" (Hold on tight!).
* "Hold my hand" (meaning "support me, be with me"): This translates as "Tiens ma main" (formal) or "Prends ma main" (informal).
* "Hold my phone" (meaning "please hold this for me"): This translates as "Tiens mon téléphone" (formal) or "Prends mon téléphone" (informal).
2. "Hold my..." as a way to emphasize the following action:
* In this case, you would likely use a phrase like "Attendez un peu" (Wait a minute!), "Regardez bien" (Look closely!), or "C'est parti!" (Here we go!) to emphasize the action.
Example:
English: "Hold my beer, I'm going to do something crazy!"
French: "Regarde ce que je vais faire! Je vais sauter par-dessus cette clôture!" (Look what I'm going to do! I'm going to jump over this fence!)
It's important to consider the specific context and the intended meaning of "Hold my..." to find the best French equivalent.