slå en sjua - Wiktionary, the free dictionary

Literally "to hit a number seven," of debated origin.

slå en sjua (present slår en sjua, preterite slog en sjua, supine slagit en sjua, imperative slå en sjua)

1. (idiomatic, colloquial) to urinate (of a man)

   Synonyms: kissa, kasta vatten, slå en drill

2. (slang, rare) to smoke or make a joint made by two papers laid together perpendicularly (so the filter part has a thicker layer of paper)