This pattern conveys that a feeling or desire is so strong that you can't hold it back. It's like saying "I can't help but..." or "I'm dying to..." in English. The emotion is overwhelming and often physical, such as hunger, curiosity, or annoyance.

It attaches to the て-form, but note that for verbs it's the plain て-form (e.g., 会いたくてたまらない), and for adjectives it's the て-form of the adjective (e.g., 嬉しくてたまらない). For na-adjectives and nouns, use でたまらない (e.g., 不便でたまらない).

The phrase is common in both speech and writing, but it's a bit more emphatic than just saying とても. It often appears in casual conversation, but can be used in formal contexts when expressing strong feelings. Avoid using it with objective facts; it's only for subjective emotions or desires.