It's great to play with your baby - but it's best to keep your roughhousing to a minimum and to follow these safety tips.
Tossing: Your baby is not a bag o' potatoes - never toss him about. Free-falling more than just a few inches can hurt your baby. A fun activity for most babies is to be lifted high into the air and lowered smoothly, but never toss him up and take your hands off him.
Ground play: Ground play is generally safe - pretend gentle wrestling and so on. However, really watch what's going on. Your baby may surprise you with a hard pinch or poke, and if you're rolling about, you could hurt your baby, if you move quickly in surprise.
Careful bouncing: Babies (most) love to bounce. Your baby's little body is not mature enough to handle too much bouncing. Be very care that you never let his head shake back and fourth due to you bouncing him. Gently bounce your babe on your knee or try slow dancing with him, giving him little bounces while you have your palm placed gently on his neck and head.
Watch his mood: If your babe isn't into roughhousing he's going to stiffen his body up and be more likely to get hurt. When you play with your baby, make sure he's actively interested.
