1. 나중에 재준이가 손이 발이 되도록 빌어서 겨우 다시 기분 좋게 헤어질 수 있었지만....
=> 재준 later apologized on all four, which managed to bring normalcy between us so we could at least split up with a smile.
* 손이 발이 되도록 = (lit.) until your hands become your feet -> groveling on all four (to apologize).
2. 내가 갑자기 물건들을 뒤져 대니 검비가 고개를 갸웃거리며 야옹야옹, 신이 나서 쫓아다녔다.
=> As I started to rummage the things out of the blue, 겸비 followed me around with excitement meowing and tilting its head to one side.
* 뒤져 대다 = 뒤지다(rummage) + -아/어 대다 (do something repeatedly making a fuss).
3. 그것들을 만지고 있자니 가슴 한 구석이 먹먹해져 왔다.
=> Feeling those things in my hand, I felt a lump rising in my heart.
* -자니 = as I end(ed) up doing something (even if I didn't exactly want to).
4. 재준이가 여자 속옷 사이즈 따위를 알 리 없었다.
=> There was no way 재준 would have known the underwear sizes of a girl.
* 따위 = things like; such sundry things.
* -ㄹ리 없다 = it couldn't/can't be; something doesn't appear to be true or possible.
5. 거울 앞에 서 보니 가관이 따로 없었다.
=> Standing before a mirror, what I saw looked ridiculous beyond comparison.
* 가관 = lit. beautiful image/scene, but only used in a sarcastic sense; something ridiculous looking.
* 따로 없다 = lit. there's no other like it -> (something) is truly (some quality) beyond comparison.
6. 팬티는 가느다란 끈에 세모꼴 천 조각만 달랑 달려 있어 가려 주는 데라곤 없었다.
=> The panties were nothing more than a little triangular patch with thin strings attached, hardly covering anything.
* 가려 주는 = 가려 주다(cover/hide for you) + -는.
* 데라곤 = 데(place) + -라고는(the most it was/did for something) -> even in the best case.
* 데라곤 없었다 = there was none even in the best of circumstances.
7. 섹시하기는 커녕 우스꽝스럽기 짝이 없었다.
=> It was comical like you've never seen, let alone anything sexy.
* 짝이 없다 = 짝(buddy, something comparable)이 없다 -> unmatched in some quality (usually in a negative sense).
8. 이 사이즈가 나한테 가당키나 하냐?
=> Does this size even come anywhere close to mine?
* 가당키나 = 가당하기나 = 가당하다(is appropriate/sane at all for) + -기나 (at all).