Waves lapping against the shore are just looking at the shore and going back into the sea; with Kakekotoba (one of waka's oratories), it also means that I cannot see you at night, just reproaching you and going home (Kokin Wakashu, Love vol.3, 626).
あふことのなぎさにし寄る浪なればうらみてのみぞ立ちかへりける（古今・恋三・626）