"whenever they please" is correct and usable in written English.
You can use it to describe a situation where someone is able to do something without restrictions. For example: "The students can take their exams whenever they please."
Since the city does not regulate protests, demonstrators are free to block traffic whenever they please.
Would they believe they can turn it on or off whenever they please?
Surely that is the point of private housing – that the owners can sell up whenever they please.
So the futures have attractions for traders who want to be able to sell short whenever they please.
Hikers can now travel pretty much anywhere they please, whenever they please, save for certain beaches, which are closed seasonally to protect species like the snowy plover.
The fact that mushers can choose to begin their daylong pit stops wherever and whenever they please confounds an intuitive understanding of the race hierarchy, and may help explain why the m.c., in Anchorage, referred to the Iditarod as "the world's greatest math and science lesson".
Most of the interviewees felt entitled to have sex whenever they pleased, and also believed that the prostitutes enjoyed having sex with them, on top of being reimbursed.
Indeed, Mr. Bush backed off his proposal this year for lifetime savings accounts, which would let people earn investment income tax free and spend it whenever they pleased.
This revolution principle--that, the sovereign power residing in the people, they may change their constitution and government whenever they please--is not a principle of discord, rancour, or war: it is a principle of melioration, contentment, and peace.
The honourable key holder would be able to enter and exit the monsterless city at night whenever they pleased.
The seven had made an agreement that they could all visit the new king whenever they pleased, except when he was with his wife.
