On Thursday, Tusk told May "the ball is now in your court", during a meeting between the pair in Downing Street in London.
He added that his goal is to establish the "closest possible" relations between Britain and the EU.
Tusk said he wants Brexit to be a "velvet divorce".
He repeated his assertion that there will be no formal exit talks until the British government triggers article 50 of the Lisbon Treaty and kick starts the formal process of leaving the EU.
May's spokesperson said the meeting was "an opportunity in part to talk about the process of leaving the EU, how we see the upcoming months, but also to talk about the upcoming October European Council and some of the issues that we expect to be on the agenda for that."
Tusk's meeting followed a consultation in Dublin on Wednesday with Irish Prime Minister Enda Kenny.
Both meetings come ahead of an informal EU summit of 27 leaders in Bratislava next week.
After the meeting with Kenny and on the summit on 16 September, Tusk said, "We will be meeting to discuss what Brexit means politically for the future of the EU. I know that Brexit is a very disorientating prospect for Ireland, a committed EU member.
"Sooner or later, your biggest trading partner - and the country with which you share a long history- will not be. The consequences of this are serious, also for the situation in Northern Ireland."
He said that both he and Kenny were "working together closely to ensure that your country does not suffer from a decision that it did not make."
Tusk added, "The Bratislava summit is not about Brexit per se. It is about bringing back political control of our common future."
His comments come after Brexit negotiator Michel Barnier told the annual meeting of the Bruegel think in Brussels on Wednesday that he is ready to start Brexit negotiations "tomorrow."