Non, pas du tout; c’est une expression dans un registre très familier, voire légèrement vulgaire, à mon avis. Elle signifie « You can go whistle for it. ». Elle a les équivalents suivants, mais dans des registres différents ;

• Tu peux (toujours) courir. (registre familier)
• Tu peux te brosser. (plus familier que « Tu peux courir »)

There’s a series of sarcastic expressions based on this pattern.

Tu peux toujours rêver

…is the original one (I think). It means "you can dream all you want about it, it’s unlikely to happen". The idea is that dreaming about something doesn’t help to make it real.

The "toujours" part of the expression is optional.

Then, there are popular or even vulgar variations in which the idea of dreaming is replaced with the idea of other actions, all equally unhelpful.

The most common ones (in my experience) have been:

Tu peux toujours te gratter (lit. you can scratch yourself all you want)

Tu peux toujours te brosser (lit. you can brush yourself all you want)

But there are many others

Tu peux toujours te fouiller (older, lit. you can think about it all you want)

Tu peux toujours te l’accrocher (older, lit. you can always hang it somewhere)

Tu peux toujours te la mettre sur l’oreille (lit. you can always put it on your ear)

They all mean "stop having unrealistic expectations" with various degrees of color.

In British English, the expression “suit yourself” does not mean “in your dreams” or “go whistle for it” or “fat chance”. It is less dismissive. It often simply means, but a little more informally, “as you wish”. It can be dismissive, but certainly not as strong as sarcastic, depending on how it’s said. An accurate translation for the general usage is literal: “comme vous le souhaitez” or “comme tu le souhaites”.