• back-to-back
• back-to-backs
• back-to-back-to-back
• back-to-back connection
• back-to-back connections

back-to-back (suomeksi)

• peräkkäinen (a: sequential or consecutive)
• perättäinen (a: sequential or consecutive)
• seläkkäinen (a: with one's back facing somebody else's back)
• seläkkäin (d: with back facing somebody else's back)
• selätysten (d: with back facing somebody else's back)