lottery, raffle
籖 centers on drawing lots or raffle tickets, typically made from bamboo slips. The two given meanings are closely related applications of the same idea.
籖 combines 竹 (bamboo) with 韯, which likely contributes the sound. The bamboo top suggests the material used for early lottery slips.
The bamboo top 竹 hints at bamboo sticks used as lottery tickets. The lower part 韯 looks like a complex container holding the drawn lots.
For セン, picture a bamboo lottery box sending out winning tickets: send -> セン, and the bamboo slips are drawn.