I have a 3 year old who is somewhat of a sissy.
Cries over everything, always calls for his mommy etc.
How do I toughen up my son?
You need to start boosting his self confidence.
My boy was a little cry baby. To make matters worse, at 4 he started coming home from school with bruises all over him. He turned out he was getting picked on by the little bully and his pals. I could have easily sorted it out with their dickhead dads but that wasn't going to help him at all. He had to do it himself.
The first thing I did was buy him some boxing gloves and me some sparring pads and trained him how to hit/fight. He is a quick learner (that was why he was moved up a year at school, and one of the reasons for why he was getting picked on), and within a couple of months could hit hard with his weight behind his punches and could move relatively well (for someone his age) too. Yet the bruises remained..
This would go on until he was 6. I had been training him for well over 18 months and could he have smashed them way before but he didn't. Because he was still lacking the self confidence needed.
Anyway, when he turned 6 (my partner wouldn't let me send him boxing), I signed him up for MMA classes. After about a month he was doing some light sparring with a kid who was 10 and nearly twice his size. My boy got stuck in and landed a nice combo and hurt the him. Afterwards, the kid said to him that he hit hard and they trained together for the rest of the class.
In the car on the way home I complemented him on his training and told him that did well against the big kid earlier. He then told me that kid said that he hit hard etc. I said to that that kid was twice the size of the kid picking on him, and that if he hurt the kid tonight, imagine what he could do to the one at school.
The next day the kid and two of mates trapped my boy behind a little plastic house in the playground, my boy sorted out all three of em lol. The bruises stopped over night, and the littlle kid who was bullying most of the class lost his mojo, and within a couple of weeks went from the bully, to all of the other kids exacting their revenge on him. Now that kid is the class joke, and doesn't bother anyone anymore.
Not only is having self confidence good for that sort of thing, it has also helped my son climb to the top of the class with his grades (not forgetting that he already skipped a class), it has also toughened him up, but has not turned him into a bully either. He doesn't need to pick on other kids to feel good. He starts secondary/middle school in september and is looking forward to it without fear. I am also sending him and my 8yr old daughter boxing in september. My missus has come round to it.
Anyway, all that wall of text just to say that you don't really need to toughen him up so to speak, you just need to give him self confidence. Never talk down to him or call him a sissy because that is what he will think that he is. Encourage him, and then get him into boxing classes as soon as he is old enough. Having self confidence will be something that will help him in nearly every part of his life