Cuisle mo chroí the anglicised meaning is "pulse of my heart". Sometimes "cuisle" may be spelled "chuisle". This aspiration occurs when it is being used as a form of address, following the vocative...
Commonly it means 'peach' as in 'momoiro' meaning 'pink' (literally: peach color), but with different kanji (writing) it can also mean 'thigh' as a body part.