drop in someone's lap
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.
drop in someone's lap
Give to someone suddenly or without warning. What is given may be desirable, as in I'm just going to drop the promotion in her lap this afternoon, or it may be burdensome, as in They simply dropped the employment problem in our laps. The former usage dates from the mid-1500s, the latter from the mid-1900s.