This one is easy. Assuming you’re not rushing off to work, and have a little time to spend, this move is always good fun and can set the tone for the day together.
Let her get in the shower first and have her shower as normal. Then time your approach to when she would be just about ready to get out. If you’re not sure, go a little earlier rather than later. If she’s already out of the shower, you’re basically screwed as you can’t really ask her to get back into the shower without looking like you failed the timing.
The approach is pretty simple. You get into the shower with her. This is a fairly obnoxious / strong / alpha move in that you are clearly invading her personal space, but you’re her husband so you shouldn’t have too much of an issue breaking her down.
Have a line ready to disarm her if she seems a little shocked at the invasion. Almost the sillier it is the better. You’re trying to convey playful fun, rather than a dangerous scuffle in the shower seeking penetration. Big goofy grin, light tone. Suggestions;
“Pardon me I didn’t know this shower was occupied”
“The hotel sent me up to you, but I’ll need some ID”
“You seem familiar, have we met”
“Shhhhh, don’t tell my wife I’m in here with you”
“Shower Boy” (say it in the same tone as “Room Service”)
“Reporting for duty”