When a guy and a girl have sex in a shower with the water on full heat. Sometimes using shampoo/soap, but always hot enough to cause the entire room to steam up.

When you're cuddling with a girl and you roll onto her with a boner and try and get her to judge your dick size.

Adj.
The act of steamrolling is to
A. When in bed with another to roll over them while laughing histarically
B. During sex when the girl is on top she does a motion like "the worm" over your body which flattens you to the bed.
C.When a girl makes you cum so hard you lay flattened against the bed.

B usually leads to C and A might lead to B if you play your cards right.

While boning a girl doggie style standing upat the top of a large, steep stairwell... You jam your thumb in her asshole and punch her in the stomach so some steam builds, then push her down the stairs so she rolls down releasing the built up steam along the way.

When your lying naked with your girl in
bed and you decide to roll all over her fully erect
yelling "I'm a Steamroller" "I'm going to roll all over you"
while laughing hysterically.

When you and your partner shit all over the bed and roll around in it, in log position, like a steamroller

When a woman drag’s her her butt cheeks and vagina across a mans face is a sliding motion.