咥える[kuwaeru] to hold in one's mouth
咥えこむ[kuwaekomu] to hold fast deep in (one's mouth or other orifice, often used in a sexual context)

指を咥える[yubiwokuwaeru] to look on enviously while doing nothing

のめり込む[nomerikomu] to be completely absorbed in
圧し込む[heshikomu] to push into
意気込む[ikigomu] to be enthusiastic about
引込む[hikikomu] to draw in
引摺り込む[hikizurikomu] to drag in

引っ込み[hikkomi] retreat
引込思案[hikkomijian] reserved
引っ込む[hikkomu] to draw back
引っ込める[hikkomeru] to draw in
運び込む[hakobikomu] to carry in