DuckCorp Dico

Found 2 definitions

1.                 From Japanese-English FreeDict Dictionary ver. 0.1:
                   
   
   
                   
                     
    (ateji (phonetic) reading)  夜這い /(en)tʃˈaɪniːz(ja)lˈe̞tə (en)tʃˈaɪniːz(ja)lˈe̞tə ˈi/, 婚 /(en)tʃˈaɪniːz(ja)lˈe̞tə/, 婚い /ˈi/, よばい /jo̞bˈäi/
   (noun (common) (futsuumeishi))
    (noun or participle which takes the aux. verb suru)
   creeping at night into a woman's bedroom, stealing into a girl's bedroom at night to make love, sneaking visit
   
                   
                 

2.                 From Japanese-English FreeDict Dictionary ver. 0.1:
                   
   
   
                   
                     
   婚 /(en)tʃˈaɪniːz(ja)lˈe̞tə/, くながい /kˌɯᵝnäɡˈäi/
   (noun (common) (futsuumeishi))
            Note: archaismsexual intercourse