Goa is a 365 days holiday destination. but I prefer to avoid April and May due to heat. though I had visited Goa in last April. daytime on beach has been quite hot. you can visit North Goa beaches, church, famous clubs. water sports, scuba is to do activities. South Goa and Dudhsagar fall is also enjoyable.
Since it's very hot now, if you guys have not visited do experience Goa in the monsoon. it's off season but amazing to experience in that season. try checking out the other side of Goa i.e. Palolem / Cola Beach side.