A [[bulge]] on top of, or next to someone's [[ass]]. Often seen with [[dry humping]] or with sexual foreplay before [[anal]] [[sex]]. 

Use with [[dry humping]] if both characters are clothed.
Use  [[Imminent anal]] / [[after anal]] and [[penis on ass]] when nude.

h4. Related tags: 

* [[bulge press]]
* [[erection under clothes]]