You could do something like the following;
Dim tp As New ToolTip()
Private Sub OvalShape1_MouseHover(ByVal sender As Object, ByVal e As System.EventArgs) Handles OvalShape1.MouseHover
tp.Show("OvalShape tooltip", ShapeContainer1, OvalShape1.Left, OvalShape1.Top, 5000)
End Sub
Private Sub OvalShape1_MouseLeave(ByVal sender As Object, ByVal e As System.EventArgs) Handles OvalShape1.MouseLeave
tp.Hide(ShapeContainer1)
End Sub