When is it safe to static stretch?

Just curious. I've heard that it's really good to stretch after a hot shower because it warms you up without involving muscles, like running or jogging to warm up. But are there any other ways. Is it okay to stretch in the morning? I really need to stretch my hip flexors more.

Yes and yes. It is good to stretch in the mornings. animals do it, and we should too. Static stretching is not unsafe, it is just not overly effective at increasing ROM. Perform PNF stretching (aka CR stretching) when you are warm, and do a couple times a week to get most bang for your buck with increasing flexibility. I would say, don't static stretch immediately before sports activities. Dynamic stretching is better as a warm up, and some studies suggest a higher injury rate and worse performance if you static stretch alone before sports.

If you need to stretch more then stretch more.