Long-sleeve dress shirt with jeans. Tucked in or not?
It's more about proportion than being too casual or not. An untucked shirt should still flatter your figure- for example, if your shirt tail is too long, it hides more of your legs and makes you appear shorter. Also, classic cut shirts have a tendency to create a tent shape around the waist and add an easy 10 pounds to your look (especially from a profile). For this reason, I strongly suggest a modern/slim/fitted dress if you would like to wear it untucked. It will fit and look natural, instead of looking sloppy. My guide for your shirt tail is that the sides hit around the bottom of your belt and the front and back should still show off you ass and package. This is like cleavage to women, don't hide your assets!
9 Answers
Always un-tucked, but not all dress shirts work with jeans. Some are too long and look ridiculous if you try to wear them un-tucked with jeans.
Generally, I like to wear more casual button downs with jeans, not the dress shirts that I'd wear with a suit or slacks. Something like a worn in Oxford always does me well.
I'm no cowboy but I generally tuck my shirts in. I'm tall so they look ridiculous if you don't. If it's short enough, and kinda casual/not ironed, untucked works. Wear it untucked with sandals or non-dressy shoes. Otherwise I don't think tucking a shirt in will make anyone mistake you for a cowboy...unless it's denim.
As long as you don't try to pull off wearing a french cuff shirt with jeans, you are fine either way.
It's more about proportion than being too casual or not. An untucked shirt should still flatter your figure- for example, if your shirt tail is too long, it hides more of your legs and makes you appear shorter. Also, classic cut shirts have a tendency to create a tent shape around the waist and add an easy 10 pounds to your look (especially from a profile). For this reason, I strongly suggest a modern/slim/fitted dress if you would like to wear it untucked. It will fit and look natural, instead of looking sloppy. My guide for your shirt tail is that the sides hit around the bottom of your belt and the front and back should still show off you ass and package. This is like cleavage to women, don't hide your assets!
Definitely depends on the shirt... I have a heavier build and usually keep my shirts tucked, but I do have a couple of shirts that are fitted, and they work much better untucked
I question the logic of the original poster. Unless you work at a farm, are involved in e.g. mining business or you work part-time as a clown for children's parties, I do not see any possible way for you to wear jeans and still call yourself a man and/or maintain respectable social standing. Furthermore, to mix dress shirt and jeans is a preposterous idea. Assuming that you worked as a clown, even the dimwittest of children could assess the value of your character immediately and most certainly you would not stay in the business for very long. I personally would not let such a person muck about near my children no closer than the reach of my .577 Holland & Holland Royal.
I hope this was helpful, if you have more questions about proper attire for an adult male please ask them before you set out in a "snappy" dress even the French would consider appropriate only for a carnival.
RHWP
Unless you're wearing it with a cowboy hat and a fat belt buckle, don't tuck it in.