drop (something) in (someone's) lap
1. To present one with something unexpectedly. When Steve won the lottery, we suddenly had the chance to travel the world dropped in our laps. If the world drops an opportunity like that in your lap, you take it!
2. To foist some unwanted burden or responsibility on one. The entire project was dropped in my lap after Lydia resigned. Our son dropped his student debt in our laps when he lost his job last year.
dump (something) in (someone's) lap
To foist something onto someone else, usually some task or responsibility. Yep, management dumped that big project in my lap after Lydia resigned.